My morning route is always about get to work, so it is the shortest possible distance (diagonal arterial 6.5 m), although that will change next year as that road is up for a complete reconstruct and I'll likely have to make adjustments as the work progresses over the summer. I would not takes this route home as the traffic and parking are terrible in the afternoon.

Going home is my get some exercise ride and I have 2 basic routes (14-15m) that incorporate some bike lanes/trails/routes and offer some options for length or extension to fit my time constraints. Both also offer short offshoots for normal errands I do like bank/drugstore.

I do find there is some "safety" involved in a regular route. As there aren't lots of bikes where I commute in the city I find that if you're on a regular schedule, as are many of the cars, they see you regularly and know you will be there. I've even had a car tell me while waiting for a light soon after a rider was killed on his commute nearby that she was glad to see me and know it wasn't "her bike guy".