One of the biggest mistakes that can cause a lot of problems for someone is moving, changing their address, and not notifying US Citizenship and Immigration Services, the immigration courts, the Department of State, or whatever federal agency has jurisdiction over your case.
What happens when someone moves and does not update their address with the appropriate federal agencies?
Sometimes people think that changing it with the post office is sufficient. Unfortunately, there's no auto-forwarding of mail from federal immigration agencies. They have their process and form to ask you to update their address online. When people fail to do that, they often end up not receiving the requests for evidence, the notices of intent to deny anything relevant in their case that needs to be responded to promptly.
What often happens is those cases get dismissed without the person's knowledge. Sometimes, months and years can pass before they even discover that they missed something in the mail. So please, please, please, if you move, update your address with USCIS.