The 15" Aluminum PowerBook G4 that I got in 2003 died a year ago. Had not used it for a long time and got it out to play with some old PPC software. Was working fine, then it crashed and would not restart. All I got was a "chime of death" indicating a memory problem. Checked it out as well as I could, and I think it's really dead - no big deal, I don't need it.
My 2008 15" MacBook Pro still works but the battery died a couple years ago. Again, I don't need it and it just sits in the closet. The screen doesn't look so good anymore and it generally looks and feels old, but it still works.
My 2013 MBA is still my primary computer and I'm happy with it. So my Mac laptops tend to last much longer than needed.
Not the 2010 model, but the 2011 one (i5, 4GB RAM). Performance is not what it used to be or at least feel like. Battery is dead after 1300 cycles. Still use it as my main computer till the end of the summer vacation then probably going for the 12" MacBook. It is a great little computer though. Small yet powerful for most tasks.
Right now it's like running Sierra betas that were high in memory use due to how the OS was compiled. I'd expect that to settle down and GA High Sierra to be similar in use of resources to GA Sierra.
For comparison, I ran SL for a day on thismachine yesterday. What a difference in term of resource usage. I generally had 2gb free even when I had half a dozen tabs open in FF.