An AI shopping comparison says ‘lifetime warranty.’ Whose lifetime?

‘Lifetime warranty’ looks reassuring in a shopping comparison. I would not let an AI assistant rank it above a fixed number of years without opening the terms. The US Federal Trade Commission's warranty guide explains why: ‘lifetime’ can refer to the product, the original buyer, or how long that buyer owns the product. Its advertising guidance says the ad should make clear which life it means. The examples in 16 CFR 239.4 draw a useful distinction: protection for as long as a car runs, even after it is sold, versus protection only while the original buyer owns it. Those are illustrations, not promises about a particular brand. For a comparison I planned to buy from, I would ask the assistant to quote the duration clause and identify who remains covered after a sale or gift. If it cannot find that wording, leave the duration unresolved rather than turn ‘lifetime’ into ‘forever.’ Coverage exclusions need a separate check. This is existing US guidance, not a new rule or a shopping-tool test. Paying extra for something you hope to keep—or pass on—should rest on the promise you actually get.