When I remember to I try to rearrange my sheets after I get up so that they still cover the mattress. That's because I've got a dog who likes to sleep on the bed during the day, I'd rather she did that on the sheets that are easier to clean.
I've read that it's better not to make your bed, so the dampness created at night can evaporate. It would be even better to air out your blankets, but it's a good excuse to give myself credit for not making the bed.