I'm not going to answer the door when my mother-in-law comes over
Did your mother-in-law do something to make oyu not want to see them?
I am embarrassed by the messiness of the home.
it is rude to leave your mother in law waiting at the door if she comes all the way over to visit. Try to keep your home in a maintained order so that you are not unprepared for unexpected visits.
You think that I should just always keep my house in order? That sounds like a lot of work.
It is wrong to pretend you are not home. If you can't keep up with cleaning there are maid services you can hire to help you catch up periodically.