Hmm at least once a week... The problem is my hobbies are seasonal.
Today I cleaned my road bike.

Still gotta get some degreaser though so my rear wheel is still off. Even though we have 2-3 more months of snow left... Pretty much instantly after that though it gets real nice out and I start biking 3-6 times a week.
RC airplanes I build in the winter and fly randomly in the summer. I'm building a plane with an 8' wingspan though, so I'm not finishing that before school next year. I'll try to get the fuse/wings all done though.