Four days a week, it's about 1.3 miles one way, the other it's about 3. At the moment I'm only doing that base mileage, but I want to work up to doing extra, so that I'm commuting 50 miles a week minimum, something I managed last summer. It'll probably be when I swap to the summer bike, which is more conducive to extra miles. One difference from last year is that now we start half an hour earlier 3 days a week, so where last year I felt like leaving early enough to get some extra miles on the way in (enough to make it 5 miles each way), now I'll probably end up doing the extra mostly after work.