Somewhere in your rent roll there is a row that was right in March. You copied it forward in April, and again in May, and the lease it describes was renewed in June at a different number. The row still says March, and nothing about it looks wrong.
That is how a manual rent roll gets made. Nobody builds the month from the leases; they build it from last month, because last month was right, and they edit the rows they remember changing. The method is fast and it is honest, and it has one property that only shows up later: every row inherits whatever the row before it said. A sheet made this way cannot tell you which of its rows were checked and which were carried. They look identical, because they are.
The errors it lets in are the quiet kind. The renewal that changed the rent in the lease and not in the sheet, so a resident is billed the old figure for months and nobody is lying. The lease that started on the 14th, which has no row until the next copy, so its first charge is never created and never chased. The tenancy that ended, which keeps its row, so a vacant unit is counted as income on a roll a lender will read. The partial payment that lives in your memory as the rest is coming Friday, and on the sheet as paid.
At twenty units you catch these without trying, because you hold the whole portfolio in your head and check the sheet against it every time you open it. Growth takes that away twice. The rows multiply until a wrong one is no longer conspicuous, and the memory that caught it is split among more people, or stays with one person, who becomes the only one who can produce the roll. The sheet never breaks at a particular size. It is a little wrong at every size, and growth is what makes it visible.
The cost does not arrive as a bill. It arrives as rent that was never charged, which is rent that was never chased; as the owner who learns their building's number from a sheet you would not have signed; and as the refinance where the lender's first question is which of these rows you can tie to a lease. Those are the moments a rent roll exists for, and a copied roll meets each of them with last month's answer.
A copied row is last month's answer with this month's date on it.
Handled differently, there is nothing to copy. Each charge comes from its lease on the lease's own schedule, so a renewal changes one record and every later charge reads it. The lease that started on the 14th has a charge on the 14th. The tenancy that ended stops producing rows, because there is no row to carry. A charge due on the 31st falls on the 30th in a short month without anyone deciding so. The roll stops being a document you maintain and becomes a report you open, and your first look at the month is a list of exceptions instead of a search for them.
Scaalr generates every rent charge from its lease, every night, on the lease's own frequency and due day, and a charge that already exists for that lease and date is never created twice. Why manual rent rolls break at scale, the schedule cases a roll has to handle, and the seven-step check against the lease file are in How to Keep Your Rent Roll Accurate as Your Portfolio Grows.
For the complete guide to keeping a rent roll accurate as a portfolio grows, see: How to Keep Your Rent Roll Accurate as Your Portfolio Grows.
The first 5 units are free, then $0.99 a unit a month, and the rent roll is on every plan.