Reliability - what’s your experience been?

My worst experience was a Denon DN 720P music streamer. I believe it was their first around 2012. After 5 years, they would not provide firmware updates for installed music platforms or the internet radio. On the other hand, I have a Velodyne SPL 1000 Sub from 2000. Never faltered and I won't replace it until it dies. 

I've only had one problem in 45 years of this hobby.  Not counting the blown tweeters in my Altec Lansing speakers (some dumbass cranked them too long during a frat party).

I bought a used conrad-johnson Premier 17LS2 preamp.  It was just old enough to start having issues.  I didn't want to mess with trying to get it fixed, so I returned it.  

Never had any trouble with my conrad johnson PV-14L.  

VPI turntable.....never a problem. (replaced drive belt twice in many years.....Alll electronics are Ayre.....one fuse was replaced after many years.....Vandersteen speakers.....a pain to set up but reliable.

I had a Sumo preamp lose a channel.  Never could get it fixed and a tweeter went out on a KEF Reference speaker and not from abuse.  Everything else has been maintenance like a turntable belt or replacing some tubes.

Three power switch failures. A very limited production pre-amp (no switch available), a Philips turntable ( I repaired the switch), and a Jolida amp (I replaced the switch).