Which factor does NOT significantly affect mail delivery times?

The factor that does not significantly affect mail delivery times is the recipient's age. Delivery times are typically determined by logistical factors such as the distance the mail needs to travel, the service class chosen (like First-Class, Priority, or Express), and the operational capabilities of the Postal Service.

Distance is a crucial factor because longer distances naturally require more time for delivery. The service class also plays an integral role, as different classes have different delivery time guarantees, impacting how quickly mail is processed and delivered. The operational capabilities of USPS, including staffing, technology, and transportation resources, directly influence efficiency and timeliness in delivery.

In contrast, the age of the recipient does not impact how quickly mail can be delivered. While it may affect the likelihood of someone being home to receive or retrieve mail, it does not influence the systemic processes involved in mail sorting and delivering, making it an irrelevant factor in terms of mail delivery times.