Still running my T500 here
I bought it second hand seven or eight years ago. Since then it's had two new SSDs (first a speed upgrade, second for capacity), more RAM, and three new power supplies when the cables give up. Surprisingly still the same battery though - I don't use it on batteries a lot.
Running Ubuntu MATE. Fan sounds a bit like a chainsaw these days but other than that the darn thing just won't die. And much as I'd like to I can't really justify buying a new one until it does.
Side note: I particularly like the T5xx-series as a compromise between full-size machines and portables. Nice big screens and keyboards. My work-supplied T440 is nowhere near as nice, though that may also be because the T440 is the worst ThinkPad ever made.