For a consistent daily commute I like my current distance- 10.2 miles with a shorter 8 mile option when I need it. That gives me a round trip of 20 miles per day. If I were a fair weather commuter with maybe a max of 2 or 3 days a week I could go for a 30 mile each way commute. Since I use my bike as a primary means of local transport that means in addition to my 20 mile round trip commute I'll add on anywhere from another mile or two to ten or more on most days. So adding more miles to just my commute can mean a lot of total miles in a day.