In the summer I use a full screed inner cover (Texas gets HOT). In the winter I have been using a full cover canvas ducking cover...lets the moisture out...keeps the heat in. So, that means I have to change cover twice a year.
Then I ran out of canvas ducking covers last year...and in a pinch found a piece of old tee shirt big enough to lay over the screened cover.
Last week when I was popping the tops for a quick peek I discovered that on one of the ducking tops either the bees...or a wax moth...had eaten a hole in the ducking.
So....DUH...from now on I'm leaving the screened covers in place year round and just laying a piece of cloth over the screen when it gets cold and I need to stop the drafts. The bees glue it down to the screen with propolis so it stays in place over the winter...and I can either wash or throw away the piece of cloth...