I try to do the complete commute (17 miles one way)at least once a week throughout the year. The other days I ride (5 miles one way) to a carpool in a nearby town. I mostly ride on rural paved roads with a minimal amount of highway riding. I've discovered lots of hills along my routes that were previously hidden by the accelerator in my automobile. :-)
I'm in my mid forties and completely enjoying my return to bicycle transportation after a 30 year hiatus. It's the best thing I've done for my health in a long time.
I've had a few close calls with motorists crowding me out or just plain not seeing me. I am constantly amazed at how loud and noxious automobiles are since I started biking again last year.
I'd recommend lights, mirror, flash flag, and helmet as necessary commuting equipment.