Building Microsoft cannot have been a low-stress endeavor, and people always remark how quickly Presidents visually age during stressful political times.
I agree that Presidents age over the course of their term.
But there are many differences between being Potus and the head of Microsoft.
President is a short term job (in general) and it is entered into later in life after I would guess a less stressful (than being President that is) life.
Gates started Microsoft when young and grew into the job over time. Not to mention that being the captain of that ship is greatly different (in terms of the "masters" that you serve) than being a politician.
Not having done either it's hard to really decide what the real differences are. But my guess is that Gates obviously had a tremendous amount of support from people hand picked over the years to carry out his wishes and way more latitude to do what he wanted which a President doesn't have. I think that factor alone is good with reducing stress of a job. (Being more in charge of your destiny, being more in control).
Also although I don't have photos to show I do remember there was a demarcation point where he started to just "look older". That didn't seem to coincide with just normal aging.
Ballmer of course doesn't look bad for his age. (Not that that proves my point but I will point that out.)
Bill Gates brand suffered during this time, and it was definitely a high stress timeframe for him. He polished his brand by donating money (http://en.wikipedia.org/wiki/Bill_%26_Melinda_Gates_Foundati... ) and he stepped down as CEO of Microsoft in January 2000.
Google image search "Bill Gates [year]" and compare how he aged over time.
