If it ain't broke, don't fix it.
Why are so many users lining up like sheep to be herded into Microsoft's Win10 pen? Whenever I've done upgrades in the past, it hasn't been because "the flock" is doing it. It's been because I noticed a new feature I felt would be of value to me. I saw no new feature in Win8.1 and see no new feature in Win10 that would make me want to take the leap. So, why take it?
One other note. Starting with Win7 (which is what I'm using now), Microsoft made a quantum leap into the area of "licensing control" over users. If you have to replace your motherboard or do any significant hardware modifications, the OS may recognize them as "creating a new computer" ... even if you're using the same one you've been using. If that happens, you end up with a screen warning saying your OS is invalid. In short, Microsoft takes you into "their court" where you're guilty until proven innocent ... and where they have the ultimate thumbs-up or thumbs-down decision over whether you're innocent. Fortunately, with Win7, I've found about 2 or 3 ways "around" that issue that have worked for me in the past. But, I'm assuming that later versions of Windows tighten that noose of control.
One note on Win10. I understand that Microsoft has taken away a user's ability to "refuse" updates. And, they do updates on "their" schedule, not "yours." Example.
Imagine you're a college student working on an assignment due tomorrow. You get to a point where you realize you "must" visit your local library for research - and the library is only open for another hour. So, you turn off your laptop to take it with you to the library - only to be faced with this on-screen message:
"Windows is performing update 1 of 127. Do not unplug or turn off your computer until all updates are complete."
Hmmm. I think I'll stick with Win7. I've turned off Windows Updates ... choosing to do them manually about once a week, just before bedtime (so I can sleep through them).