Memory is not a record. A simple ledger, updated as payments arrive, is the difference between "I think they owe two months" and a table you can hand over.
Date, rent due, amount paid, the period it covers and the method. Part-payments and top-ups get their own rows; the running balance column keeps the true position without mental arithmetic.
A positive balance means rent is outstanding. Negative means the tenant is ahead. Note the convention on the sheet itself so nobody argues about it later.
A ledger written up on the day carries far more weight than one reconstructed before a dispute. Five minutes a month is the whole cost.
The ledger is your running record; receipts are the per-payment proof. Using both means each document backs up the other.
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