We do sit-down band at least once a week starting around the 3rd week of school, usually 2-3 days/week by mid-October. It gets concert horns on faces (for those who play something else for marching), cleans out the ears. Since starting that a few years ago we've had better tone quality both indoors and outdoors, and better scores all around. We lose a bit of marching rehearsal time for the week, but the benefits are worth it. We do a mix of fundamentals, chorales, and reading music for winter concert.

I've heard of programs doing a fall concert. I can't imagine where that would possibly fit into the calendar.