My winter bike got tuned up this summer and got a lower drive gear, better fenders, and new brake levers but is was already good to go.
My gear gets checked, mostly to make sure it's all where it needs to be in case the weather turns... and it can turn on a dime here.
If stuff is worn out it gets replaced.
I might swap out the Schwalbes for some bigger fatter Panaracer XC Pros but we'll see about that... they have served me well for winter riding.
This is the most important item on my winter cycling list... the U.A.V.