Property Management
Property management is everything between buying a rental and selling it: advertising vacancies, vetting applicants, chasing rent, dispatching repair crews and keeping up with local law. It is the fee that often decides whether a BRRRR rental cash flows, and it becomes the bottleneck when an investor repeats the process across many properties.
The default deal budgets 8% of rent, or $352 a month on $4,400. Many managers also charge a leasing fee when they place a new tenant and a markup on repairs, so the full cost can run above the headline percentage.
Budgeting for management even when self-managing keeps the numbers honest. With cash flow of about $161 a month after the refinance, the default deal has little room for an expense that was left out.
Further reading: Property Management on Wikipedia.