Maybe you are moving and wondering whether to sell or keep the old place as a rental. Maybe you bought a home with an in-law suite. Either way, becoming a landlord looks simple from the outside: collect rent, pay the mortgage, keep the difference. The reality has more moving parts, and the difference between a rental that quietly builds wealth and one that eats your weekends is almost always decided before the first tenant ever moves in. Here is what to get right up front.

Run the real numbers before you decide to keep it

Start with the honest math, not the hopeful version. Take the monthly rent similar homes nearby actually get (not the number you feel yours deserves) and subtract everything:

  • The mortgage payment, taxes, and insurance — and note that landlord insurance costs roughly 15% to 25% more than a homeowner policy.
  • Repairs and upkeep — budget about 1% of the home's value per year.
  • Vacancy — assume the home sits empty about one month per year between tenants.
  • Property management, if you use it — typically 8% to 10% of the rent.

Positive cash flow is not the only way a rental pays

If the rent covers all costs with money left over, that is positive cash flow, and it is the comfortable version of landlording. But a rental that only breaks even each month can still build wealth three quieter ways: the tenant's rent pays down your mortgage, the home tends to rise in value over the years, and the tax code lets you deduct expenses and depreciation against the rental income.

The version to avoid is meaningful negative cash flow: feeding the property hundreds of dollars a month and calling it an investment. That only works if the home's value is climbing fast, and fast is never guaranteed. If the honest math shows a deep monthly loss, selling is usually the better move.

Screening the tenant is the whole game

Nearly every landlord horror story traces back to one rushed decision: accepting a weak tenant because the home was sitting empty and the mortgage was due. A vacant month costs you one month of rent. A bad tenant can cost you a year of rent, legal fees, and repairs.

Screen every applicant the same way, both because it is fair and because fair-housing law requires it. Verify income (a common bar is monthly income of three times the rent), run credit and background checks through a proper screening service, and actually call previous landlords, who have no reason to lie for a tenant they were glad to see go. Write your standards down before you list, and apply them to everyone equally.

Know the rules before you collect a dollar

Landlording is regulated, and the rules are local. Many cities and counties require a rental license and a basic inspection before you may rent the home at all. Security deposits are commonly capped (often at one or two months' rent) and in many places must sit in a separate account, sometimes with interest owed to the tenant.

Two more that surprise first-timers: homes built before 1978 come with federal lead-paint disclosure duties, and if you have a mortgage, most loans require you to have lived in the home for a set period before converting it to a rental. And if the home is in an HOA, check the rental rules first — some buildings cap how many units may be rented at once. None of this is hard, but learning it after a tenant moves in is expensive.

Decide honestly: self-manage or hire it out

Self-managing saves the 8% to 10% fee and works fine for one nearby property, a solid tenant, and an owner who answers the phone. Be ready for the unglamorous parts: the 10 p.m. leak, chasing a late payment, and keeping up with changing rules.

A good property manager earns the fee by advertising the home, screening tenants, handling every repair call, and staying current on the law, which matters double if you live far away or simply do not want a second job. The middle path many owners choose: self-manage the easy years, and hand it off when life gets busy. Whichever you pick, keep a reserve fund of at least two to three months of expenses, because the water heater does not check your cash flow before it dies.