For myself, Iam ambivalent. It would probably depend on what I was having done, my financial situation, what the problem was, and how I would look after it. I accept the fact that people age, or have things that they dont like with their bodies. I dont think I would want to have it just to look 40 when I'm 60 or 70.
As for my wife, that is complete personal choice. Even if she aged, I would never say, "I think you need a face lift", or if I wished I had someone with a bigger chest, (Which I'm not into because I'm not a breast man) I wouldnt say to her: "I would like it if you had bigger breasts", because that would be hurtful and rude to her, and I'm not like that, especially with people I love. I accept people for what they are, and chances are if shes 50, 60 or 70 and she doesnt look perfect or young, I probably dont either. If she wanted to do something, I would never stop her, but as for promoting it, I dont think I ever would.
Mitch