as others have mentioned, i really like having two bikes ready to go for winter bike commuting.

on one bike, my main commuter, i have conti GP 4 seasons for when the streets are dry or just wet (above freezing).

and then i have another bike that wears schwalbe marathon winters (studded) for whenever ice threatens.

i don't trust any non studded tire over ice after a couple of bad spills during my first year of winter bike commuting before i got wise to studded tires, but riding on studded tires when the streets are clear and dry is a literal and figurative drag.

last winter was so freaking mild in chicago that i only rode my studded tire winter bike a grand total of 14 times (a record low for me), so it sure was nice to have the other bike with non-studded slicks to ride for the vast majority of last winter's days when conditions didn't call for studs.