Dry roads are no problem. The challenge I have is once snow is on the ground, even if it's dry and sunny there are often puddles and roadway moisture that is unavoidable. Hit a few of those and you'll find salty grime all over your bike. No big deal if you wash it off - but also washing bikes in the winter is a bit more challenging too.
I have a few bikes that I ride in really gross conditions (cyclocross and winter road riding). At the end of the season, I'll have my LBS overhaul these bikes. They strip the bike down to the bare frame, clean everything, replace cables, replace or repack/grease bearings, overhaul the rear hub, install new bar tape, etc. This service is usually around $200 and my bikes come back looking and feeling brand new.