I'd guess that for most people on this sub forum, commuting racks up most of the miles. So a good question might be, are there any real differences between bike commuting and the kind of utility cycling we do?
One thing I am concerned about in running errands is that I'm constantly dealing with locking and unlocking my bike. I have to deal with all kinds of bizarre bike racks (or none at all) and also removing and putting back things like the water bottle, the frame pump, the bike computer, lights and blinkies, loads, the underseat bag, etc. etc. etc. This is a big nuisance especially when you try to accomplish four or five errands on a trip.