Common Rental Expense Mistakes
Most deals look better before the full list of costs is written down. Here are the ones I see missed most often.
The story
I once modeled a property using only the mortgage, taxes, and insurance. It showed a few hundred dollars a month positive. Then the water heater failed in month four and the tenant called about a leak. Those two items wiped out the cushion for the rest of the year. I had no reserve line in the original analysis. After that I started treating repairs and vacancy as real monthly costs instead of surprises. The monthly number got smaller, but the surprises got rarer.
Known mistakes
- Leaving repairs and maintenance at zero because the property “looks fine.”
- Using zero vacancy because you plan to keep it rented.
- Forgetting property management even if you self-manage at first.
- Underestimating insurance or taxes based on the current owner’s bill.
- Ignoring utilities the owner pays, HOA fees, or lawn care.
- Not updating the expense list after the inspection report arrives.
What I would do if I were starting over
- Create a simple monthly expense list before looking at any listing.
- Include mortgage, taxes, insurance, HOA, utilities you pay, and a repair reserve of at least 5 to 10 percent of rent.
- Add one month of vacancy per year until you have a track record with that property.
- If you might hire a manager later, include a management fee in the model even if you start self-managing.
- After the inspection, add any immediate repairs as a one-time cost and adjust the ongoing reserve if systems are older.
- Recalculate cash flow with the full list. If it only works with optimistic numbers, pass.
- Review actual expenses after six months and update the model so the next deal is more accurate.
Expenses are not the exciting part of the analysis. They are the part that keeps the monthly number honest. Write them down early and keep the list longer than feels necessary.