I think I generally have 3-4 at a time which includes my BOM.
I always have 2, for variety or maybe assembly-line fashion like Klue, but what happens is that I decide to make a new special-occasion gift so I add that. I can only start projects with deadlines way in advance so that means I have that one added on for awhile. I try to wait on the next desired project until the deadline one is done. So, I still can't take the time to learn kaleidoscoping until this baby quilt is done (getting close) and then my daughter's 30thBD wallhanging (haven't even planned yet). Then I'll go back to my BOM, my lapquilt for ME and learn kaleidoscope. I'd like to try tote bags for Christmas gifts but I'll have to see if that's when I'll be packing to move. I only have a small window of energy each day.