Today is it: traditionally, December 15 is the highest-volume shipping and mailing day of the entire year. The U.S. Postal Service will process 640 million cards, letters, postcards, periodicals, catalogs, and packages today alone. FedEx is doing its part, processing 22.6 million packages today. UPS says that its busiest day will be next Monday, as people try to get last-minute Christmas gifts to their destinations.

Instead of offering free shipping and guaranteeing that items will arrive before Christmas, retailers are taking a more conservative approach this year. Amazon won’t guarantee delivery by Christmas for items ordered with standard shipping after this Friday; Prime members who get two-day shipping can order next Monday. However, these deadlines only apply to items that are in Amazon’s own warehouses. Items from Marketplace sellers that those vendors ship are separate, which is something that may be confusing to customers later on. Make sure that you know who you’re ordering from.

Don’t be surprised if you see a delivery driver for any of those services on an unexpected day like Sunday this year. UPS, USPS, and FedEx are all delivering packages to consumers seven days a week in order to avoid a backlog like last year that had drivers stopping by on Christmas Day with last-minute orders.

Busiest day of season for FedEx, postal service [CNN] (Warning: auto-play video)

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