Home Insurance
Home insurance covers damage to a dwelling and the owner's liability for injuries on the property. Once tenants live there, a homeowner policy no longer fits; the property needs landlord or dwelling fire coverage, and that premium becomes a fixed cost against the rent after the BRRRR refinance.
The default numbers assume a $2,500 annual premium. Most refinance lenders collect it monthly through escrow, roughly $208 with each payment. Landlord policies can add loss-of-rent coverage, which pays the rent while the property is unlivable after a covered loss.
Coverage changes across the BRRRR timeline. The rehab period often needs a vacant or builder's risk policy, then a rental policy once the tenant moves in. Premiums in some regions have climbed faster than rents, so a current quote beats an old estimate.
Further reading: Home Insurance on Wikipedia.