1. There are few guarantees come the holiday season.

When the holidays roll around, all the major mail and package delivery services recommend that you plan well ahead for shipping. In fact, the United States Postal Service (USPS) suggests that if you mail anything after Dec. 13, you use its Priority Mail service rather than sending it regular parcel post to ensure timely delivery before Christmas.

That s one reason to consider private delivery companies, but most don t offer much protection should they fail to make the holiday deadline or if there s a mistake in delivery. United Parcel Services (UPS), for example, suspends money-back guarantees on its most economical services during the peak season roughly Dec. 11 through Dec. 25. There s also a $15 surcharge for Saturday deliveries. At FedEx, the last day to guarantee Christmas delivery with Ground or Home service is generally seven business days before Christmas.

Your best bet, especially after Dec. 20, is USPS s Express Mail, which can deliver even on Dec. 25.

2. It s hard to collect on our so-called insurance.

Individuals who send valuable items in the mail or via UPS or FedEx should find out what would happen if the package is lost or damaged. That s because they may have difficulty getting a delivery service to pay up when a package is damaged usually the fine print of terms and conditions protects companies from many incidents that can happen while a package is in transit. Often the delivery service can claim the packaging was insufficient, say, without enough padding.

With both UPS and FedEx, all consumer packages are covered up to $100 automatically. Beyond that amount, customers are on their own. FedEx doesn t provide insurance of any kind, a spokeswoman says. Instead, the company has a contractual limit of liability. If an individual declares a higher value for the package they re planning to ship, the maximum they would be allowed is $500 with items like jewelry, antiques or paintings, she says. Beyond these amounts, the consumer bears the loss, although they can purchase a separate insurance policy elsewhere.

At the USPS, customers can purchase insurance for the value of the items they are mailing in person at the post office or online. Insurance can typically provide up to $5,000 indemnity coverage for a lost or damaged item. Consumers will need to hold on to the insurance receipt. When submitting a claim, they ll need to provide proof of damage, loss, or loss of partial contents.

3. Junk mail is our bread and butter.

When you move, the only surefire way to have your mail forwarded is to fill out the USPS s official change-of-address form. But once you do, you could start getting even more junk mail and direct marketing pitches along with your bills and magazines. While the USPS says it doesn t sell new address information to direct marketers, it does charge a licensing fee of $175,000 per year to third-party companies that are hired by direct marketers to take their old direct-mailing lists and revise them using the change-of-address information provided by the USPS.

The USPS says that licensing its National Change of Address database to these so-called list cleaners helps to save it money in returned mail and forwarding mail costs. The official line is that all mail delivered by the Postal Service is legitimate and valid. No mail is illegitimate, especially not advertising mail, says a spokeswoman. We don t determine what you should receive. If it s placed in the mail, we deliver it. You may think a catalog is junk, but what if we thought your sports magazine was junk?

4. Timely delivery isn t our biggest priority.

The United States Postal Service says its Priority Mail is a two- to three-day delivery option within the U.S., but paying $4.90 to send a priority mail flat rate envelope this way may not be better than simply slapping on a first-class stamp. First-class mail letters weighing up to one ounce cost 44 cents in postage, which varies by weight, and can cost a maximum of $3.26 for a first-class 13-ounce package.

A USPS spokesperson says Priority Mail is a convenient, reliable, and affordable service that does not claim to include a guarantee, and that unlike its competitors, the Postal Service doesn t add fuel or weekend surcharges.

However, according to a 2009 report by the Postal Regulatory Commission, an independent agency, 96.1% of single-piece, overnight first-class mail was delivered on time during fiscal year 2009 near perfect, but a slight drop from 96.5% in fiscal year 2007. Cheaper deliveries are less punctual. Two-day mail was on time 93.5%, which fell below the 94% target for the year and lower than the 94.1% figure reached in 2007. Package services on-time delivery hit 73.4%, below the 90% target, and periodicals were at 73.7%, below the 91% target.

Still, in most cases, you ll pay more for express delivery through private carriers: For example, a package weighing one pound or less sent from New York City to Philadelphia via FedEx s two-day service costs about $14.50. But unlike the USPS s Priority Mail, in most cases, it comes with a money-back guarantee.

5. We might not advertise our best deal for shipping.

Media Mail service has been around for years, but few people use it because it isn t well publicized down at the local post office. That s because Media Mail is primarily used by business customers, according to a USPS spokeswoman. But anyone can use it to mail books, films, printed music, sound recordings, manuscripts, or CDs and DVDs. Just be sure that s all that s in the package: To be shipped using Media Mail rates, a package cannot contain advertising or a letter to Mom, and the maximum weight is 70 pounds. And, if a postal clerk is suspicious of a box or envelope s contents, he can open it for inspection.

Media Mail delivery can be a little on the pokey side up to nine days for delivery although it can often take fewer days. If you re not in a rush to send the package, this could be a helpful way to save money. Mailing 20 pounds of books using Media Mail from New York to California costs $8.59, compared with $23.98 for shipping them standard Parcel Post. Otherwise, customers who need to send a package quickly like within two days are probably better off not using this service, says a spokeswoman.

6. Your lost package is probably sitting in a warehouse somewhere.

Just because you don t receive a package doesn t mean it s lost. In many cases, you ll have to contact the mail or package deliverer to track it down. UPS, for example, has an overgoods location for packages that are missing labels and are therefore undeliverable. Many of those items are eventually delivered or picked up, says a spokeswoman. The UPS stores goods for at least three months, or five months if it s a personal item.

FedEx Express hangs on to undelivered goods for three months and often longer for personal or family-type items and some tech equipment. FedEx Ground holds on to lost items for six months. The USPS can hold on to lost mail or packages anywhere from 30 days to a year.

After that, items are destroyed, donated to charity, or sold through auctions. Your best hope for recovering a lost package is calling customer support and requesting a search on the service s warehouse database, which lists detailed descriptions of packages contents. Meanwhile, cover mailing labels with clear tape, and place a return address label on the inside of the package. We ll open a box before it ends up at the warehouse, a UPS spokesman says, and look for any information that might help us figure out where it s supposed to go.

7. If I m afraid of your dog, I may not deliver your mail.

According to the USPS, 2,863 letter carriers were bitten by dogs in 2009, an average of nine dog bites per delivery day. For that reason, the USPS will stop mail delivery to your home if the carrier feels threatened by your pet. And if he believes your dog just might come after him while he s next door or across the street, he can refuse to deliver mail to your entire block. Until the situation has been fixed to the postmaster s and mail carrier s satisfaction usually meaning that your dog is restrained while the letter carrier is working everyone involved may have to pick up their mail at the local post office.

In the event of an actual incident, your mail carrier can also sue you. As the dog owner, If you don t have homeowner s or renter s insurance, you could be responsible for footing the entire claim for medical bills and damages, says Todd Peterson, a personal-injury lawyer based in Portland, Ore., who has represented delivery people attacked by dogs. [One] letter carrier I represented had a quarter-inch scar on his calf from a dog bite, Peterson says. He sued the dog owner and won $8,500.

While posting a beware of dog sign can help prevent an incident, it s usually best to keep the dog in a back room while signing for packages. Also, the USPS recommends that dog owners make sure children don t accept mail directly from a delivery person, as a dog may see the transaction as a threatening gesture.

8. There could be spies at your local post office.

If the line at your local post office always seems long, the problem may be exacerbated by USPS employees who sometimes go undercover as mystery shoppers. The purpose of this operation is to make sure clerks do enough suggestive selling and that they re asking customers questions, ranging from how fast they want their mail delivered to whether they need services such as delivery confirmation. While the USPS confirms that such questioning is required, a spokeswoman says, the mystery shopper program helps customers make better-informed decisions.

To get the best deal for your package and avoid extra time listening to these offers check out the USPS web site where you can price different mailing methods beforehand. And to avoid the line completely, you can use the Automated Postal Center machines in your post office s lobby. These do-it-yourself systems will weigh your mail, price it and print the appropriate postage. You can also print postage online at usps.com/clicknship.

9. There s a cheaper way to send packages abroad but it s not widely promoted.

Sending a three-pound holiday gift to your friend in France using USPS s standard airmail, Priority Mail International, will cost you $34.10 unless you know a secret that could make it cheaper, and USPS may not be telling. Sending that same package by First Class Mail International would cost $24.42.

A USPS spokeswoman says clerks are trained to ask customers specific questions in order to sell them a product that meets their needs. She adds that Priority Mail International should arrive faster than First Class Mail International but that the number of delivery days to a destination varies by country. In addition, she says that this first class option could present drawbacks for consumers because it doesn t offer a tracking option or insurance.

Even so, you re better off checking usps.com ahead of time. In some cases, you could save more money using a flat-rate envelope or a small flat-rate box, assuming the item fits. Flat Rate envelopes are not available for First Class Mail International but are available for Priority and Express Mail International.

10. Elm Avenue is really Elm Street. That ll be $10.

Not filling out an address label correctly won t just create a major headache when it s not delivered to the right location it also costs money to fix the error. And that could be the case even if the mistake is fairly minor: Say you write "Drive" instead of "Boulevard" but list the right city and zip code.

UPS, for example, charges a $19 address-correction fee for UPS Ground services and $11 for UPS Air. FedEx charges up to $11. Both offer address-checking services on their web sites so that such mistakes can be avoided. That s a legitimate cost to us, a UPS spokesman says. I would love to show people what our employees go through trying to correct an address after packages get brought back to a UPS center. We actually resort to combing through phone books, he says.