If you make a hundred bucks, the saying goes, you'll probably need to spend at least $50 of it on survival — rent, groceries, heating your house. Then, $30 can go to the fun stuff, things like seeing friends or buying gifts for your family.
And as for the final $20? You should probably tuck it away for a rainy day or retirement. That's based on the 50-30-20 rule, a common rule of thumb that tries to get within shooting distance of what you'll need to cover expenses in your golden years. Estimating how long you'll live, after all, is an imprecise art, and everyone has different incomes, tastes and spending habits.
RELATED: 31 money hacks that will make you rich:
31 easy money hacks to help you get richer every single day this month
31 easy money hacks to help you get richer every single day this month
1. List at least one item you aren't using on Craigslist or eBay.
Not only will this help you clear out clutter, but it will turn an unwanted item into cash. If you get inspired and want to sell more, check out this Lifehacker guide to turning unwanted junk into cash.
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2. Pack your lunch instead of buying it.
Time calculated how much someone in New York could save by bringing a brown bag lunch ($3) versus buying lunch ($15). At that rate of savings, if you packed lunch instead of buying it every day for a decade, you'd save $31,200. Calculate how much you would save using this Bankrate tool.
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3. Change out at least one incandescent bulb to a CFL.
According to Consumer Reports: "By replacing a 60-watt incandescent bulb — the most common household bulb — with a spiral-type 13-watt CFL that produces an equivalent amount of light, you could save more than $57 over the life of the CFL."
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4. Program your thermostat to turn off while you are at work or sleeping.
According to Energy.gov, "You can save as much as 10% a year on heating and cooling by simply turning your thermostat back 7°-10°F for 8 hours a day from its normal setting."
5. Delete your stored credit cards from online accounts.
Have your credit card stored to make one-click purchases? If you instead have to manually enter your card each time, you make buying online more of a hassle, which will limit impulse purchases.
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6. Eat meatless.
Many people have adopted Meatless Mondays to help save money and the planet. Start this Monday and see if you can make it a habit.
7. Buy a re-usable water bottle.
Consumer Reports calculates that bottled water costs $346 a year, while tap water costs just $0.48. If you are using bottled water, stop now and start refilling a water bottle instead.
A Planet Money report found that half of all members of one popular gym never go — and theWashington Post reports the gym industry actually relies on members paying for, but never using, the service. Don't let money be auto-debited monthly for anything you don't actively use. Call now to cancel, and read Mic's guide to getting fit for free.
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11. Make sure you are using the right bank.
Check out what unnecessary fees you pay for ATM use and for maintaining a monthly account. If you're paying anything, it may be time to switch to a different bank: Check out Mic's guide to some of the best banks to use in 2016 to 2017 and see how your bank compares. If your bank falls short, make the switch.
12. Open an IRA, if you don't already have one. If you do, check on your investment mix.
An IRA is one of the best ways to save for retirement because you can potentially get tax breaks for investing in it. Check out this 5-minute guide to retirement savings to find out more and follow this simple step-by-step primer on opening one. If you already have an IRA, use an asset allocation calculator to see if you have the right mix of investments.
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13. Create (or review) your budget.
Read up on the basics of how to budget so you can determine the steps you need to take to get a handle on where your money is going. You can also use recommended budgeting apps to make the process easier.
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14. Make sure you are using the right credit card.
Figuring out the best credit card for you is a matter of looking at your usage and needs. If you carry a balance, it's time to shop for a low APR card with a 0% balance transfer. But if you are a responsible card user, aim for a card with big cash-back perks or rewards.
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15. Clean out the air filters in your car.
Pro Car Mechanics explains: "The benefits of a clean air filter are almost immediate. Airflow goes back to the proper level to mix with the gasoline. It has been estimated that replacing the dirty air filter will increase MPG on the car up to 10% and also generate a fuel savings of close $.15 per gallon at the fuel pump." Cars Direct explains how you can clean out your car's air filter.
16. Review your debts and make sure your repayment approach is optimized.
If you owe money on credit cards or loans, review the interest rates, terms and repayment strategy. If you have high interest debt, refinancing could make sense.Think through your debt repayment strategy and evaluate whether you can or should make extra payments.
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17. Call your cell phone and cable companies.
Go over your monthly plans to find out if you are paying for services you don't need. Ask for any discounts that could potentially help you to spend less. Check out these tips for saving money on cable TV.
Learn to let out pants, tailor your own skirts, change the oil in your car or fix a stopped up sink. Wisebread has a list of 10 life skills to learn to save money.
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20. Call your insurance agent.
If you have car insurance, homeowner's insurance or renter's insurance, you may be able to lower your deductible, bundle your policies or get rid of coverage you no longer need. Investopedia lists 6 ways to save on insurance.
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21. Print, cut, or buy coupons.
Using coupons can help you save on groceries, dining out and other items you buy. Browse sites like RetailMeNot for printable coupons or use TheCouponClippers to purchase cut coupons from the newspaper. Focus on items you are going to buy anyway. You might also visit websites like DealSeekingMom to find out how to get items like toothpaste and toilet paper for free — or close to free.
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22. Unsubscribe from daily deal sites or online websites.
If you are subscribed to a bunch of sites that alert you to sales and bargains, you are more likely to spend on items you don't need. Buy stuff when you decide you need it, not when an online newsletter tells you the item is on sale.
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23. Go for a walk instead of watching TV.
You won't waste the electricity on running the TV — and you won't see ads shilling for products. Plus, walking is a healthy and free way to get exercise.
24. Plan a weekend of free events.
Make a commitment to not spend any money this weekend. Look for free community events to attend — or invite your friends over for a potluck or clothing swap party.
25. Plan your meals for the week.
Meal planning allows you to avoid wasting food since you can make a grocery list and buy only what you need. Lifehacker has a simple guide to meal planning and you can check out Mic's tips for healthy eating on a budget.
26. Cook and store food strategically.
Following your meal plan, make up a few meals you'll eat over the course of the week. You can even make some extra to freeze for when you're in a rush and don't have time to cook or pack a lunch a few days later: Just portion out food in little freezer bags so it'll be easy to thaw individual meals.
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27. Have a no-spend day today.
Make a commitment not to spend even $1 on anything for one whole day. Prep your coffee at home, bring your lunch, bike to work, and eat one of your pre-planned, home-cooked meals for dinner.
28. Automate all of your bill paying ... and saving.
If you are still manually paying your bills each month, set up automation for any accounts you can. This helps you avoid late fees if you get busy or forget. If you have a savings account, set up an automated transfer of at least a few dollars per month so you can make sure you are saving something.
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29. Find a cheaper way to commute today.
If you normally Uber, try taking public transportation. If you normally take public transportation, walk or bike to work. If you drive, see if you can arrange a carpool or switch to the bus. Your commute can cost you thousands over your working life.
30. Call HR and ask about workplace benefits.
You should definitely be investing in a 401(k) if your employer offers one. However, you may be eligible for other benefits like corporate discounts on cell phone service or hotel rooms. Find out what benefits are available that you can use to save — you might be surprised (see: "cash in lieu").
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31. Carry around healthy snacks bought in bulk.
It's not just meals that are a money suck, and hitting the vending machine can add up. Buy some dried fruit, granola bars or trail mix in bulk — and then bag it up into snack-sized portions to help your wallet and your waistline.
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The figure is also probably a bit aspirational. Many Americans would have trouble saving 20% of what they make — roughly 11 million use up the entirety of that 50% survival figure on rent alone, to say nothing of food and other necessities. Flat wages plus rising living expenses is one possible explanation for why 69% of Americans have less than $1,000 in their savings account.
Still, even if 20% savings might seem out of reach, financial planners are not pulling that number out of nowhere: Research suggests that as a golden rule it comes pretty close to ballparking what a 25-year-old making $40,000 would need to save annually to retire comfortably by age 67: about 22%.
There's an important caveat there, especially if you're in your 20s — odds are, you'll probably work a little beyond age 67. That's especially true if you can save only the minimum amount financial planners suggest, around 10%.
But don't stress! Just by thinking about these questions, you are already ahead of the curve. Here's a little primer to help you figure out exactly where you stand — and how much you need to beef up your savings game.
How much money to have saved by age 20
Here's a more uplifting tip: The earlier you start saving, the less you need to save each month — and it's super smart to start putting away cash long before you take your first full-time job. We're talking babysitting money, or even that high school graduation check that you're not sure what to do with.
If you have anything at all in the bank by age 20, bravo. You're in good shape.
Consider putting that cash into a Roth IRA. Individual retirement accounts can easily follow you regardless of your career ups and downs, and with a Roth account, the money gets taxed going in as opposed to when you take it out.
Translation? It's an ideal way for a broke-ass college student to start their nest egg, since odds are you'll be in a higher tax bracket 40 or 50 years from now, when you're ready to start taking the money out.
How much money to have saved by age 25
As you get deeper into your 20s, you should shoot to have about one quarter of your annual cash (25% of your gross pay) saved up, according to a spokeswoman for the budgeting app Mint. That means that the typical 25-year old might want to have somewhere around $10,000 in savings.
Curious about where you stand?
Averages for 20-somethings range widely: One median figure suggests young people have about $16,000 saved for retirement, according to a 2015 study by Transamerica. But other research has suggested the true figure may be lower. A Wall Street Journalanalysis of savers aged 25 to 34 found that the median account had only $13,500 saved, and that more than half of millennials didn't have a retirement account at all.
In other words, something is still better than nothing.
How much money to have saved by age 30
Once you're 30, figuring out a hard number gets a little trickier, since the stakes are a little higher. Fidelity suggests that by 30 you should have saved about one times your annual salary saved.
The median income for 29-year-olds is roughly $35,000 per year, according to the Atlantic, which means that by 30 you would ideally have about that stashed away — though of course there will be exceptions, especially if you've gotten an expensive graduate degree that took you out of the workforce.
Other income readings suggest you should probably have saved up even more: According to the Bureau of Labor Statistics, the median weekly earnings for U.S. workers aged 25 to 34 would amount to about $40,000 annually.
How much money to have saved by age 35
Your 30s is when the push to save for retirement heats up: Data from a 2015 New York Federal Reserve report suggests that this decade is when your earnings really start to ramp higher. By the time your 30s are over, odds are you're within $1,000 of your peak salary.
So it's time to get serious: Fidelity suggests you have about two times your annual salary saved by age 35.
If you earn the median weekly wage for a 35 to 44 year old, you might make close to $50,000 — which means you probably want about $100,000 saved.
How much money to have saved by age 40
Your 40s are when your finances start to get a lot more complicated, which is why it's also the age where it's increasingly helpful to consider paying a professional to help you make a plan and stay on track.
On the flip side, if you've been hitting the goals so far, by now you've built up pretty consistent savings habits, which means you might not have to depart too much from what you're already doing.
A common benchmark for age 40, according to Fidelity, is to try and save three times your current annual salary, which could mean about $150,000.
How much money to have saved by age 45
By 45, the traditional goalpost is to have saved up around four times your annual salary, according to Fidelity, which might mean about $200,000 or more. Alas, again, even that number might be far too low for you — and depends on the standard of living you hope to maintain in retirement.
Remember that this is the point in life when Fed data suggests you should stop expecting major salary increases down the line.
How much you need to save depends on when and how you want to retire. To sustain your quality of life, you'll likely need between eight and 11 times your annual pay by retirement, not counting Social Security.
Some estimates suggest that people may need between $1million and $2 million dollars by old age — though again, it will depend on your lifestyle.
If you learn to live on less, you may need less. But if you want to be in true ship-shape, keep in mind estimated goals for your age group. The estimates really do range — so don't get too hung up on dollar amounts — but do understand the rules of thumb enough to stay on track.
Remember: Saving is more achievable than you may realize; the sooner you start, the easier it will be. You might even get to retire early.
Sign up for The Payoff — your weekly crash course on how to live your best financial life. Additionally, for all your burning money questions, check out Mic's credit, savings, career, investing and health care hubs for more information — that pays off.