keep using windows 7 or 8.
you can't do it forever, what if they drop the support in the future, actually it is certain, as it happened with windows xp, you will be running a very unsecure software with your bitcoin client
at the same time, i feel less secure in holding coin on windows 10 because of this anti-privacy crap, even if the system is 100 secure erased before installing everything
I have windows 10 and all my wallets in the pc
do I have to worry ?
No if you want to be more careful though go to the search function and type in privacy settings, there you can make sure to turn everything off and you'll be no different then using a previous version. Microsoft won't risk millions of dollars and flop their newest OS by stealing Bitcoin wallets.
this is true only because bitcoin has a tiny market cap, but what if one is holding 100k bitcoin with a value of 100k each, it would be 10B, microsoft market cap is 340B if they can find 34 guy wallet like that or bitcoin reach 1M per coins one, i'm sure something will change
well you can always do the offline trick for your cold storage....