My commute is 11 miles each way. Conditions are fairly good MUPs. It takes a little over an hour in the morning which is mostly flat and downhill and a little over an hour in the afternoon which has quite a bit of uphill.

I could come close to doing it every day of the week but I don't think this would help my general physical preparedness any more. While biking is good conditioning, it does nothing for your upper body strength or your posture. While there is no doubt in my mind that a person that bikes 5 days a week at least 10 miles each way is going to be in great shape, there will be some imbalances in your life and physical wellbeing. Maybe if you are in your 20s you can do other athletic pursuits at the same time. But I'm in my 40s and have a demanding job, wife, kids and house to care for. I'd rather bike 2-3 days per week and do other things for my strength like weightlifting, sandbags, kettlebells etc. for my strength rather than bike 5 days per week. However, I'm glad that I have the time and option to always bike more if I feel like it.