One, just one
I have bought one PC in my life. Everything else has been upgraded or bought piece by piece. As such, the three PCs I have today are the result of this endless recycling of stuff.
In all this time (since the dawn of the upgradeable PC in 1990 or so), I have only had one piece of equipment fail catastrophically : a PSU unit that up and blew a capacitor. I had just enough time to shut down the PC properly and unplug before it started smelling of burnt plastic.
That is the only case I encountered where something went so badly wrong on my PC equipment.
Along the way I've had a few hard disks die, like everyone else I think, and I fried a motherboard one day plugging something in that I shouldn't have plugged there.
But all in all, my PC equipment has been absolutely stellar. I have motherboards from early 2000 that still work. Actually, it has only ever been my insatiable appetite for upgrading that has cost me so much money in equipment. That, and the fact that I have never purchased a laptop in my life. Don't trust the things.
Won't trust Surface either. I prefer sitting at a proper desk, in a good chair, with mouse, keyboard and two 26" widescreens, thank you.