I can answer some of this for you. Most surgeons will say a deep plane FL will last 15 years before aging/gravity brings your face back to being less youthful. Not everyone will continue to do lifts, there are other options, threads, fillers, CO2 lasers, etc. I have heard having 2 face lifts is not uncommon.
If your surgeon does not do deep-plane (full muscle realignment) then your face lift will maybe last 5 years. If your surgeon says he can do it in-office it is not a deep-plane facelift and you are better served looking elsewhere, just my .02.
Great skincare and diet, water, all the good things really do help minimize the effects of aging, but genetics will also play a large part in how each of us "ages".
I would be surprised if any surgeon would perform a facelift on you if you are just 40. Also, there is full (eyes/brow/low face/neck), then there is just upper face, just lower face, and low face with neck. Which our necks often give our age away. Not everyone needs every area tweaked...a board certified surgeon can best advise on what is best for you.