Every transaction affects two accounts. Rent received increases cash and decreases what the tenant owes. A repair paid decreases cash and increases expenses against a unit. A deposit received increases cash and increases what you owe the tenant. Each entry has a matching counter-entry, and the totals must agree.
This sounds like bookkeeping pedantry until you consider the alternative.
Why a list is not a ledger
A single-entry system is a list of money in and money out, which is what most property spreadsheets are. It records what happened but cannot prove it is complete. Anything omitted is simply absent, and nothing anywhere indicates that it should have been there.
In a double-entry system, an omission usually breaks the balance. The system tells you where it disagrees with itself, which is a property no list has.
The four things it lets you reconcile at once
For property management specifically, this is what makes the books answerable:
- Arrears: what tenants owe.
- Deposits held: what you owe tenants.
- Expenses: what was spent, against which unit.
- Amounts owed to landlords: what you are holding to remit.
Each of those is a real obligation to a real person, and each is a figure someone is entitled to ask you to prove. A set of books that balances can prove all four simultaneously. A set of lists cannot prove any of them, however carefully it was kept.
A worked entry
Tenant pays KES 20,000, allocated KES 18,000 to September rent and KES 2,000 to August water.
| Account | Debit | Credit | | --- | --- | --- | | Bank (client account) | 20,000 | | | Tenant receivable, unit 2A | | 20,000 |
The tenant's balance falls by exactly what the bank balance rose by. If somebody later edits the receipt to KES 22,000 without a matching entry, the ledger stops balancing and says so.
Compare a spreadsheet: change 20,000 to 22,000 in a cell and nothing anywhere objects.
Corrections
A mistake is fixed by a new entry that reverses it, leaving the original visible. Never by editing the original.
This is the same principle that makes a receipt history worth anything: a record capable of being silently changed proves nothing, including the entries that were right all along. An append-only history is slightly uglier and infinitely more defensible.
What goes wrong
Deposits posted as income. The most consequential single error. A deposit is a liability, and posting it as revenue means the books show money you do not have the right to.
Expenses posted with no unit. A repair recorded against "maintenance" and not against unit 2A cannot appear on that landlord's statement, which means it either goes unrecovered or gets added by hand later.
The bank is never reconciled to the ledger. Double entry proves the books are internally consistent. Only reconciliation to the bank proves they describe reality.
It is abandoned under pressure. A busy month, a shortcut, and three transactions get entered on one side only. The balance breaks, nobody has time to find out why, and the tolerance for a broken balance becomes permanent.