An extended warranty, properly called an extended service contract (ESC) or vehicle service contract, pays for covered mechanical and electrical repairs after the factory warranty runs out. Whether it is worth buying depends almost entirely on how long you will keep the car and how a surprise repair bill would land on your budget.
Coverage levels range from powertrain only (engine, transmission, drive components) up to exclusionary or bumper-to-bumper style plans that cover most components except a listed set of exclusions. All plans exclude normal wear and maintenance: brakes, tires, wiper blades, oil changes, and cosmetic items are on you.
Plans differ in deductible (commonly $0 to $200 per visit), where you can get repairs done, and extras like rental car and roadside coverage. The contract, not the sales pitch, is what counts: read the exclusions page.
No. The factory warranty comes with the car from the manufacturer. An ESC is a separate contract, from the manufacturer's program or a third-party administrator, that begins paying after (or alongside) factory coverage ends.
Often yes, while the vehicle still qualifies by age and mileage. Buying at purchase lets you finance it into the loan; buying later means paying cash but gives you time to compare providers.
Generally yes: cancel within the full-refund window (often 30 to 60 days, unused) for everything back, or later for a pro-rated refund of the unused portion, usually applied to your loan. Terms vary by contract and state.