Grandfather's Axe
Same here.
3 PCs 2 cases are 8 years old, other for watching films about 4 years.
Graphics cards 5 years+, monitors too.
HDDs replaced when they start to fail or at 5 years.
Anything that needs more than the 32GB RAM that's in the 2 main PCs is only used briefly, so is shunted into Azure. Doesn't cost anything when it's turned off.
I doubt I'll ever replace the cases, just the internals as they wear out. I do fancy a bigger monitor (2 x 24", 1 x 20" at the moment), but not all applications can cope with super high resolution screens.
Sadly, my Surface Pro is unlikely to last more than 3-4 years.