Will all my devices (printer, mouse, etc.) remain connected when I upgrade to windows 10?

[zynotrov]

Or will they have to be reinstalled?

 

[xandros9]

Overall, you probably won't have to worry about any device.

There's a chance one of those things won't play nice, but I'm willing to bet everything will go with minimal fuss. Or at least Windows will handle driver installation for you.