This time of year, I really try to fire up the pit every weekend. I'm also finding that by doing shorter cooks, I'm able to squeeze in more days by the pit. I'd love to do a big brisket or pork butt every weekend, but life just gets in the way. Doing a couple tri-tips, chickens, pork tenderloins, sausages, etc., really helps maximize my opportunities by cutting the cooking time in half.
As for late fall and winter, I mentally move into chili and gumbo season so the pit doesn't get as much use. But as with most cities in this region of the country, you can get the occasional 70-degree February day (followed, of course, by a foot of snow the very next day), and I always take advantage.