I’m hardly a heavy/regular library user but between picking up discount passes, picking up a video now and then, donating books, using a library to work in when I’m in a city, and even doing research, I’m in a library a good dozen times a year. For most people, that actually would be frequent movie theater going by count.

ADDED: And furthermore, as other comments have observed, most of library visits are dropping in for maybe 5 minutes. If I were only to count the times I spend multiple hours in the library, it would probably be a couple times a year--and that's mostly because a few city libraries are often convenient places to hangout with free WiFi when I have some time between appointments/activities.