I think most small computers are just disposable, but a well built tower PC or server will last a long time.
My main PC is an old Dell Inspiron 547that I got 8 years ago. It's got an AMD Athlon processor. I went ahead and set it up then with W7 Pro 64 bit and maxed the motherboard out on 8 gigs of RAM when it was new with 2 hard drives. Later on I went up to a 7200 RPM big second drive and I had to change out the power supply once but that's it. Did my first bands CD on it and it still is plenty fine as my main stereo.
Built the OS up from scratch and updated it to Win 10.
One thing I have done with my PCs is take it out a couple times a year and dust them out. I just know from work if you keep them clean they run cooler and have less issues.
― earlnash, Friday, 8 June 2018 02:14 (five years ago) link