I've worried about constant compression of the window seals, so once I toss the full cover onto her, I open the windows. Not only does it take pressure off the seals, it allows air into the cabin. When I remove the cover, I close the windows, and I can tell that the seals take a bit of leverage to compress them in order to close the window. But...I'm on a trailer with a full cover. I'm unusually anal about keeping the sun off the gelcoat, so my experience is probably not transferable.