What sort of guidelines do folks in the northeast apply in determining how and when to stop providing space at the end of summer?

Most folks I talk to winter here in 2 deeps. What is unclear to me is when they (the bees) should be crowded down to ensure they backfill? I assume that as long as I keep giving them empty space above they will try to fill that first? So at some point I need to either let them fill out the supers completely or remove them? It seems to this newbee, that this would be a balancing act between wanting them to pack away into the 2 deeps while not doing it too early to provide plenty of space for the last rounds of brood.

Or do I have it wrong, will they backfill the brood area in fall regardless of what is going on "overhead"?