The paperwork trail that saves roommates from disputes
Save the signed lease, any landlord approvals, roommate or sublease agreement, deposit receipt, rent receipts, utility bills, and move-in photos. Keep a shared ledger for household expenses and a written record of changes to rent or chores.
Use email or a shared document for important notices: a replacement roommate, a move-out date, a repair request, or an agreement to buy shared furniture. Back up the records where every relevant person can reach them.
The point is not to build a case against friends. It is to make the facts available if memories diverge or a person moves away. Good records make fair settlements easier.