For some reason I found this thread quite interesting to read! I was sort of expecting windows 10 to snarl up at some point and need a fresh install. This is what happened to two of my PCs that I upgraded from 8 and 7 to 10. One has had a fresh install of 8 and the other has been replaced with a new PC. Both were not right since downgrading to 10. This may have been because both of those didn't have windows 10 drivers provided by the motherboard/chipset manufacturers, both intel systems BTW. My wife's PC and laptop however I both did in-place upgrades to 10 years ago with no problems since. The laptops touch screen driver actually works better in 10.
Incidentally I haven't activated windows 10 on my new PC yet, months later. It seems like you don't actually need to buy windows 10, it's like freeware that gives you some extra options if you pay that you don't really need. I even have two spare windows 10 keys but I CBA to use them LOL.