When you get a chance to learn from someone else’s mistakes, take the opportunity while you can. In a document titled “Top 10 Mailing Mistakes,” the United States Postal Service offers examples of mistakes in formatting and design that rendered the mail pieces of four real-life marketers unmailable. Here are some “live and learn” stories to sip with your morning coffee.

Cheaping Out with Index Cards: One postal customer thought it was a good idea to use 3 x 5-inch index cards to create their first commercial First-Class card design. (After all, an index card looks like a postcard, right?) I’m not sure what they were trying to accomplish, but understandably, the piece was unmailable. This falls into the category of, “If you have ever wondered about it, someone has probably tried to do it.”

Cost of Creativity: Another postal customer decided to be creative with a 4 x 4-inch card. Because the card did not meet the USPS’s aspect ratio, the marketer knew that it wouldn’t get automation rates and expected to pay more in postage. But it would make it up with better ROI, right? Not if the card can’t be mailed. Back to the drawing board.

Doubling Lightweight Paper Doesn’t Cut It: What if you want to use lighter weight paper to save money? Can you just double it up to meet the USPS requirements for minimum thickness? One postal customer discovered that the answer is no. It used a lightweight paper to create a letter-size bi-fold self-mailer to obtain commercial letter pricing. The customer knew that the mail would be considered nonmachinable because the paper did not meet the minimum basis weight requirement, but with the design being folded, it did not think that minimum thickness would be an issue. It was. When it comes to meeting mailing requirements, don’t make assumptions.

Delivery Address Placement Matters: Another customer created a letter-size card with the dimensions of 4 x 6 inches but placed the delivery address parallel to the shortest dimension of the design. As a result, for mailing purposes, the length was only 4 inches and the mail piece was not mailable. The customer had not considered that the placement of the delivery address would negatively impact the mailability of the design.

The takeaway? Close is good for horseshoes and hand grenades, but not for meeting USPS mailing requirements.  When using a new size or format or changing your aspect ratios, ask before putting it into the mail!