There are some utilities available that are supposed to improve the privacy/security of Win10 installations, e.g., [0].
My wife kept asking me if she should upgrade to Win10 and I said "don't do it". Since Win8.1 will be supported until 2023 or so, it really didn't matter. Now, thankfully, the "free upgrade" period is over and she won't be nagged to do the upgrade.
After all the years in the game, we'd think MS should know better than pulling all this crap on its users.