If you had to handle nearly 15 billion items between now and New Year’s Eve, you would say the same thing: “Mail early.”

“The sooner, the better,” said Ray V. Daiutolo Sr., regional spokesman for the U.S. Postal Service. “People like to wait to mail their presents. We certainly appreciate the business, but earlier is better, especially when mailing overseas.”

The Postal Service said it expects to process 545 million pieces every day throughout the season or more than 152 million addresses nationwide.

The busiest mailing day is projected to be Dec. 16, Daiutolo said, when more than 600 million pieces are expected to be processed. The same day, 6 million customers are expected to visit post offices nationwide.

The busiest delivery day for mail will be Dec. 18 and the busiest day for packages will be Dec. 19.

Daiutolo recommended what he calls the ABCs.

“A: Have a good address on the package, make it concise, and if it has directionals, such as north or south in the address, use them,” he said. “Don’t guess at the ZIP code. Look it up. If you can’t find the ZIP code, don’t put any ZIP code on there.

“B is for box, a good, strong shipping box with no writing on it.

“And C is for cushioning the gift and if it can be engaged or turned on while shipping, take the batteries out. Use a good shipping tape and no string.”

Ashley M. Woomer, manager of a suburban Reading UPS store, said the store’s busiest time is the two weeks before Christmas.

She also recommended a good box, as long as it’s not damaged, with plenty of room for packing peanuts to protect the items inside.

Hazardous materials cannot be shipped nor can an alcohol box, even if the contents are not alcohol-related.

“We’re not authorized to ship alcohol boxes,” she said.

Woomer had this advice: “Make sure the packaging is able to sustain a 4-foot drop. Use about 3 to 4 inches of bubble wrap.”

Common mistakes she sees are customers expecting free materials, such as tape.

United Parcel Service’s pick-up time is 5 p.m., so get there before that, or else it waits until the next shipping day. And UPS cannot deliver to post office boxes.

Bonny S. Harrison, FedEx spokeswoman, said “The box should be a few inches larger than the gift on all sides, and no torn flaps, no water damage and no old shipping labels.”

All of the shipping companies, including the Post Office, sell proper packaging.

The last day to ship for a guaranteed Christmas delivery with FedEx is Dec. 23, she said.

Harrison said FedEx’s busiest day is Dec. 2 with 22 million packages through its global network, up 11 percent year over year, and the busiest week is the same week, with 85 million shipments.