I tried to ride to work 5 straight days a couple weeks ago (around 26 miles round trip, uphill most of the way home). I only made it 4. I could've physically done the 5th, but I would've been tired the rest of the weekend. I guess i'm just not physically ready for a 5 day commute... plus by the end of the week, I wasn't enjoying it as much, and that's one of the reasons I ride.