I have winter bedding & window treatments and summer bedding & window treatments for each bedroom. When the summer bedding and window treatments are being used, the winter stuff is stored between the mattress and boxspring, and vise versa in the winter. When I’m swapping seasons, it’s also a reminder to flip the mattress.

This way, all of the queen bedding (and double window treatments) are under the queen mattress and the king bedding (and single window treatments) are under the king mattress and I don’t try to make up a bed with the wrong size sheets.