A modern guide to tipping

After consulting with numerous etiquette publications, the Emily Post Institute and CNN Money, BuzzFeed learned that you should always tip 20 percent on the pre-tax amount for most services.

Your parents probably taught you to tip 15 percent, but that's a tad old school. Many service jobs pay less than minimum wage and don't include benefits ... so if you tip less than 20 percent, you should have a good reason.

Restaurant tipping should always be 20 percent (this also applies if you eat your meal at the bar). Haircuts should also be 20 percent, and if someone else washes your hair then you should tip them $5.

Massages and tattoos are also 20 percent ... after all, those aren't easy gigs!

When you use a coupon or gift certificate you should always tip 20 percent on the non-discounted price of the item/service.

There are a few exceptions to the 20 percent rule, though.

Taxis should be tipped 15 percent, always rounded up to the nearest dollar. Pickup orders should be tipped 10 percent, since your takeout didn't magically package itself.

Delivery should also be 10 percent, however if it's a particularly tough commute tip 20 percent.

Valets? $2. Car Washes? $5. Bartenders? $1 per drink ($2 if the order was fancy, or if you really loved what you sipped).

Do you agree? Let us know in the comments below.