Title insurance is a one-time policy that protects an owner or lender against losses from defects in a property's title that existed before you bought it but surfaced afterward. Unlike most insurance, which covers future accidents, it covers the past: a forged deed in the chain of ownership, an unpaid tax bill, a missed heir with a claim, or a recorded lien the search overlooked.
There are two policies. The lender's policy protects the bank's loan and is required on almost every mortgage. The owner's policy is optional and protects your equity. The premium is paid once at closing and the coverage lasts as long as you own the property.
In practice
Say you buy a duplex for $340,000 with $68,000 down and a $272,000 loan. At closing your settlement statement shows a lender's policy at roughly $1,360 (often around 0.5% of the loan, though rates vary by state and insurer) and an owner's policy at roughly $1,700 on the purchase price. Call it about $3,000 total, paid once.
Two years later a contractor produces a recorded mechanic's lien for $14,000 from work the prior owner never paid for, filed before your purchase and missed in the title search. The lien attaches to the property, not the old owner, so it is now your problem. Your owner's policy defends the claim and pays the $14,000 to clear it. Without that policy, the $3,000 you skipped would have been the cheap part of the story.
Why it matters to a small landlord
The lender's policy is not optional, so the real decision is whether to add the owner's policy for a few hundred to a couple thousand dollars. For a rental you plan to hold for years, declining it to save that line item is the kind of false economy that surfaces at the worst time. Both premiums are part of your acquisition cost, which means they fold into your basis and your investment property closing costs rather than becoming an immediate deduction. Budgeting for them belongs in the same place you run the numbers when you buy your first rental, alongside the inspection and the appraisal.
Title insurance pays for the search as much as the payout. The work of combing public records before closing is what catches most problems while they are still the seller's to fix.
A title policy is the backstop for things the paperwork is supposed to prevent. A warranty deed is the seller's written promise that the title is clean, a lien is the recorded claim that promise is meant to keep out, and the insurer steps in when one slips past anyway. Read together, they explain why a buyer can end up with ownership no one else can challenge.