My shortest route is 10.5 miles, but I take a 12 mile route at least for better roads (the short route has 4 miles of gravel).

Unless the weather is bad, I usually take a 15 mile route, just because I get to ride a few minutes more on that route. If I could figure out how to keep getting paid for it, I'd ride straight past work for 50 miles then turn around and go home.