If nothing else, I would encourage upgrading to Windows 10 purely for the fact that I think it will last further in the future than Windows 7, which is already 6 years old--we saw what happened eventually, inevitably to XP, where they finally hammered in that last nail in the coffin and ended support for it. Despite its many flaws, it's not nearly as awful as Windows 8, I can safely assure you.
Windows 7 support will end in 2020. That's practically an eternity to me.
If it ain't broke, don't fix it. Works for me. If I'm still alive then, I'll probably treat myself to my first Mac.