Bathroom Ceiling Insulation
My first fan, I glued b.r. to the slot sides, one on each side. The wires poke between the b.r. pieces into the slots. Last cover contacted the fan frame, different than before. If you don't cover the slots, not that big of a deal, you would be sucking attic air while fan is on, letting small amount of bathroom air to attic while off.
Clothes taking longer to dry?
Clean the dryer screen in HOT water if using fabric softener sheets.
They leave a residue that impedes air-flow, costing you money.
Clean the ducting in the last six months? 17,000 dryer fires annually!