Y'know, ya got yer anagathics, yer rejuvenation therapy, yer bionics, yer organ cloning - a traveller can live a hella long time if s/he's smart, careful, and a bit lucky.
The longest I've been able to run a character was about twenty years game-time, but I'd really love to either play in or run a campaign that lasts sixty or seventy years game-time, to follow the transition from low-rent mercenaries or free traders to planetary overlords or merchant princes and beyond...