I really hope we manage to extend our lifespan greatly before I die.
I think the most realistic "great increase" in lifespan our generation may get is synthetic grown organs that are readily available, for "cheap". Organ failure is pretty much what death is all about.
If we had enough organs for transplant to go around, everyone could in theory just replace everything before it even gets "old" (assuming they can pay for it all, hehe). Of course you can't just replace the brain so... assuming optimal nutrition, proper rest, exercise, and so on, maybe we can get to live almost twice as long as previous generations?