Ok, I do dynamically reconfigure my routes on the fly.

Usually I don't worry about anything less than a mile.

Last Friday I cut about 50 miles off of my one way commute depending on how you count

Anyway, I like to make loops for RT rides. Trying to choose different roads for each direction.

I'm often thinking about new routes, and consider safety, traffic, climbing and flatness, distance, general pleasantness, and whether I'm late. Choices may vary with heavy cargo, light cargo, empty, schedule, weather, etc.

And, while I like the familiar, it never hurts to try something new.