Heya,
I'm still running several copies of Win7 on several machines. I recently did updates to take an old machine forward with Service Pack 1 and all the other updates (probably over 3Gigs of updates hah). But it still did it and works fine. All my software runs flawless still on Win7, as all of it was written prior to Win10 anyways. And I run Steam on them all and everything works flawless.
I won't change from Win7 until the software I use no longer works properly or hardware no longer works properly. Nothing wrong with Win10, I just have no reason to buy multiple copies of it at this time when everything is working. But when it is time, I'll do that, I'll just get several Win10 keys and fresh install each machine one at a time. But hopefully I have more time before doing that out of necessity. At least Win10 is now considered "mature" and most of the issues are updated.
Very best,