I was pretty sure that a time machine would in fact decrease your life expectancy, at least to the outside viewer.
You'd go about travelling all over the world in time, and yet for comfort and understandings sake, you'd always return to the same place (or thereabouts) in time.
Yet despite being in the same time as you started, you'd have aged by the minutes, hours, years... whatever, that you'd been travelling in time. Eventually this would build up, depending on how addicted you became to it, and you'd have gained a few decades on everyone around you and be physically much older than you should be.
Or the obvious answer is to travel forward to a point where immortality can be provided through technology.
Of course chances are that you'd have to stay there to facilitate the immortality, which would be difficult for most people to abandon their entire old life... On top of that, where do you get the money from? I doubt immortality is cheap.
You might say 'Oh! I have a time machine, I can do anything!' But I think you'd still need business savvy and wit to gather that fortune through time travel... I doubt it's as simple as storing five hundred quid in a bank and getting the millions years of interest for it...
Currency, banking, society would be so greatly changed...Not to mention that it'd be near impossible to prove you owned the money...
Right...I'm overthinking it...Sorry.