That's advice that rocker Kid Rock either never got or has decided to ignore.
The Motor City bad boy was on Late Show With David Letterman Monday night where he offered a little advice of his own to ex-wife Pamela Anderson's new husband, Rick Salomon.
"Over the weekend, your ex-wife Pamela Anderson got married," said Letterman.
"I wish somebody would have given me the advice that I'd like to give her husband," Kid Rock said. "'Why buy the cow when you can get the milk for free?'"
"C'mon, lighten up," Rock said, adding, "I wish them much happiness."
Last November Rock, whose real name is Robert Ritchie, 36, and Anderson, 40, filed for divorce, after less than four months of marriage.
He has made other public statements denigrating his ex-wife recently, including an accusation she faked a miscarriage as a cry for attention shortly before they filed for divorce.
Anderson posted a message on her Web site in September saying she did not want to get drawn into a public battle with Ritchie.
"He's bitter," she wrote. "It's sad to see. I don't want to battle with him. I wish him the best. I'd hate to point out habits I had a hard time with. They are personal to him and that's why we are not together. These are desperate attempts. I've moved on."