Due to a combination of factors, I might be about to sell two laptops. I dug out their original hard disks to put them back in for sale, keeping the SSDs I bought for reuse.
The first is my main personal laptop. I’ve had it for several years now so it is due for a replacement, and I’m holding off to see what Skylake mobile brings to the table. It has a 1st generation i5 mobile CPU and HD5850 mobility graphics. Good enough for its day but showing its age now, particularly in more demanding gaming. It came with Windows 7, which I had since updated to Windows 10. The original HD had Win7 on it. Due to the laptops age the manufacturer has said it will not provide any compatibility updates for Windows 10. A major annoyance was that the manual LCD brightness shortcut keys no longer worked correctly, and only had limited adjustment range. So in that sense, keeping this one on Win7 to retain that functionality seems a good option. Its GPU is too old for DX12 so that part of Win10 isn’t a significant benefit. Bit of a shame. Windows 10 itself runs fine on it. But little things in this case are enough of a longer term deal breaker for me if I were to keep it.
The second is my personal laptop I take to work. This is a smaller one used purely so I can go online at lunch without the intrusive controls on work PCs. This is a bit more modern originally coming with Win 8.0, which was still on its original hard disk when I swapped that back in. The (lack of) start menu thing stuck out like a sore thumb, so if you were to remain on 8.x, getting the update to 8.1 update 1 would be wise. But this laptop is new enough the manufacturer is updating drivers for it, so everything still works correctly under Win10. In this case I think going Win10 is a viable option.
I wont go into desktops as generally they don’t have odd stuff to trip over driver compatibility with. I will say I never updated my old Win7 desktop to Win10, and I don’t feel any urge to. I might have to uninstall that update to get rid of the Win10 nag on it, and it’ll be fine as is. If I use a spare disk, I might clone to that, update to 10, and store it in case I want it in future when the “free” update offer isn’t around any more.