Cindy Crawford opens up her home, talks marriage

Cindy Crawford and her husband of 15 years, Rande Gerber, opened up their palatial Malibu estate to former ET host Mary Hart, filling her in on how they've stayed together all these years.

One of the couple's secrets is to simply put in the extra effort.

"The good [marriages] are work," Cindy, 48, said. "The people that give up too early -- it's like what they're not realizing is that if they just put in that extra work and they get to the other side of that then you have all this history together. We were just talking about how much we both cherish that."

Another tip: know when and where to argue.

"Never on camera," Rande, 51, quipped when asked if they ever have disagreements.

Cindy and Rande have two children together -- 14-year-old son Presley and 12-year-old daughter Kaya. Kaya has already started to follow in her mom's footsteps, booking a couple of modeling gigs, while Presley is more of a surfer dude.

"We sit here a lot and watch our son surf," Cindy told Mary while taking a walk along the beach, which is practically in their backyard.