Nothing is final until you’ve got it in writing

You can agree with you mom, roommate, or spouse that you will make your bed, clean up your room, and put your breakfast dishes in the dishwasher before you go to school or work every day without a binding legal document fully executed by all parties.
You can also agree on who takes out the trash, who feeds and walks the dog, and who does the laundry without a signed piece of paper.
What you cannot do without a fully executed contract is buy or sell a house.
So here are a few situations