I upgraded to Windows 10 on my Thinkpad several months ago, encountered numerous problems and disinstalled it.
I have indicated every time I am asked by an MS pop-up that I do not want to upgrade. I do not intend to try again for as long as I have my current laptop.
To my horror, leaving my laptop on overnight I found the next morning that Windows 10 had been installed after I went to sleep. No one touched my laptop so Windows 10 installed itself. I did not ask for an upgrade, did not schedule an upgrade, did not postpone an upgrade.
I was able to revert to Windows 7 but lost 15-20 minutes of my work day because of it.
Microsoft -- leave me alone.