I would never do it & sending a bad message to my kids would be included as one of the reasons. I can see getting reconstruction/corrective surgery done if you have actyal damage, such as I've seen a coupleof pretty bad c-section scars that were puckered & beyond a typical scar. But if you have the nromal signs of age, boobs smaller than you'd like, I see it as pretty vain & teaching your kids that vanity is important.
I know someone whose dad got a nose job & liked it so much he offered to pay for his adult daughter to get hers done too. I think her nose is fine & I think she had every right to be as offended as she was that he said it. Probably the only reason she has a good enough head on her shoulders to know her nose is FINE & he is an ass is because he hasn't there been much in her life, thank God.