Most rental owners track one number, whether the rent arrived, and audit the rest annually at tax time, which is like checking your speed once per road trip. Five numbers, checked monthly, tell you the truth early enough to act on it.
The five numbers
One: collected rent against scheduled rent. Not “did they pay” but “did everything scheduled arrive, in full, on time.” Partial payments and late payments are data, and their trend matters more than any single month. A tenancy that goes full-on-time, full-on-time, partial, late is telling you something in the only language tenancies speak.
Two: maintenance spend, monthly and trailing twelve. A healthy single-family rental in San Diego tends to run 5 to 10 percent of rent in upkeep across a year, lumpy month to month. The number itself matters less than its composition: recurring small fixes on the same system are the early warning that a big replacement is choosing its own date. Deferred maintenance is a loan against the property at terrible interest.
Three: effective vacancy. Days vacant times daily rent, counted honestly, including the make-ready gap between tenancies. On a $3,500 rental every vacant week is roughly $800, which reframes decisions all season: a $400 concession that closes a good tenant this week beats a full-price lease three weeks out, and the discipline to run that math is worth more than most upgrades.
Four: rent against market. Twice a year, run real comps on your own property as if you were pricing it fresh (the how is in the May piece on verifying market rent). Under-market drift compounds quietly, and over-market renewals invite the move-out that triggers number three. You want to know which side of market you are on and by how much, on purpose.
Five: net cash after everything. Rent minus mortgage, taxes, insurance, HOA, maintenance, management, reserves, monthly, not annually. Owners are routinely wrong about this number in both directions, and both errors cost: imagined losses cause premature sales of performing assets, and imagined profits hide properties that have been treading water for years.
Twenty minutes a month
Five numbers, one evening a month, maybe twenty minutes once the habit exists. The owners in real trouble are almost never the ones with bad properties. They are the ones who found out late. Every managed property we run reports these numbers to its owner monthly, but the framework is free and it works whether or not anyone manages the property for you. Track them and the property cannot surprise you. That is the entire point.
Joe Wiseman is a licensed California broker (DRE #02043323) and owns Best Nest Property Management in San Diego.