Alas, I have to agree, hardware becomes obsolete 'at some point'. The '7 32 bit laptop still ruins nicely though, with a clean debian install and ctwm as window manager. Most of the times memory is the biggest challenge though, as even the current browsers balloon like crazy.

I've been using Linux since '94 and until now I haven't had to replace a piece of hardware running linux due to hardware limitations. Every one of them that got replaced, died on me with the dying part not being repairable or replaceable. (I even soldered a sd card slot back in place on an RPi 3)

The only 'obsolete' hardware I now have are my BananaPi R1 and R2, as software support (bananian) stopped on the R1 and the R2 still needs to be dusted off to see if it can be used. (rare hardware has it's limitations) They'll still work and function how I left them, but it's not wise to use them for the task I bought them, core router, without security updates. (so kinda more a support issue)