The parts that wear out are the ones you cannot inspect

The argument

Proponents of this position argue that a second-hand phone hides its condition in precisely the components that determine whether it will last. A battery degrades with every charge, and a handset that has been through a couple of owners may hold a fraction of its original capacity while showing nothing on the outside; the buyer discovers it when the phone cannot get through a day. Similar problems follow from drops and damp: a cracked internal frame, a weakened connector or a board that has been exposed to moisture can leave a device working on the day of sale and failing some weeks later. Proponents point out that the usual reassurances do not reach these faults. A buyer can see that the screen is intact and that the phone powers on, and can confirm the obvious functions, but cannot see how the battery has been treated, whether the device has been opened, or whether a previous repair used parts that will fail. Nor is history easy to establish: the seller may not know, may not say, and in a private sale will not be available afterwards. On this view the information needed to judge the purchase is systematically unavailable to the person making it. Defenders of the position draw the practical conclusion. A phone is not an ornament but the thing people depend on for payments, directions, identification and contact in an emergency, so a device with an unknown remaining life is a poor bargain however low the price. They argue that the money saved buys a risk whose cost falls at the worst possible moment, and that a cheaper new or guaranteed handset is the better use of the same sum. On this account you should not buy a second-hand smartphone, because its most important condition cannot be inspected.

Premises

Counter-arguments

Critics reply that the uncertainty is overstated and that much of it can be resolved: phones report their own battery health, a seller can be asked to demonstrate the device, and a refurbished handset is tested and sold with a guarantee precisely so the buyer does not have to judge. They also argue that new phones fail too, and that the relevant comparison is between the risk of a used device and the much larger sum paid for a new one, which could cover a replacement outright. Others note that the dependence described argues for keeping a spare or buying from a seller who accepts returns rather than against used phones as such.

Rejecting the premises

[Rejecting P1] Critics object that phones report their own battery health, so the most important wearing component is in fact inspectable. [Rejecting P2] They argue that a refurbished handset is tested and guaranteed precisely so the buyer does not have to establish its history. [Rejecting P3] They reply that the dependence described argues for a return window or a spare device rather than against used phones as such. [Rejecting C] They conclude that new phones also fail, so the comparison must weigh the residual risk against the much larger sum paid for a new one.