In the PNW winter, I wash my daily commute bike about 1x per two months. I relube the chain a little more often. The bike gets washed when/because it looks like hell, not because the gray schmutz and filth are really affecting its operation. The chain gets relubed when/because it gets noisy, not because I am worried about chain wear. 7 speed chain and freewheel, not expensive to replace. I think I could probably ride the entire winter without washing or relubing, if I didn't mind a filthy and noisy bike and buying a new $10 chain every now and then. Sometimes I wish I had an IGH bike with a full chaincase, but I'd still have to wash it as often, it would simply be faster to do it.