2014 which is a decent run, but I computers I've bought have been retired before they died so I expected this to last even longer. I was aiming for a 10 year anniversary! I've gotten into some basic soldering and repair work (mainly gaming) and what I've learned is that there's always a physical reason for things to stop working. So unless something burnt out (no sign of it) this thing should still be kicking.
Last month I'm pretty sure my CMOS battery went since my clock reset, but I was running without just fine so long as I had internet. I powered it off one night and then when I tried turning it back on a day or two later - here I am with no display. It powered the fans and stayed on the first few times I tested, but now it just boot loops with a clicking noise. I thought my PSU (EVGA G2) went bad just a year outside of warranty but that powered up an old desktop without issue. Since then I've replaced the CMOS battery, removed it entirely. Then pulled all of the parts, GPU and RAM removal did nothing and now I even pulled it all from the case so I am pretty convinced it's gotta be CPU/mobo. There was at one point a red LED on indicating CPU being an issue but I haven't been able to reproduce, so it's hard to say whether or not it was the mobo failing and giving a false reading or if the CPU is really the problem. No popped caps, scorches, bent pins, anything I can tell.
At this point I may check under the mobo heat sinks to see if any ICs are fried. Or maybe see if I can get a cheap as dirt LGA 1150 to determine if my CPU is fine - that would give me closure so that I'm not just getting rid of good hardware because of potentially a simple fix.