Quick answer: the EDDM mistakes that actually cost money fall into four buckets: pieces that get rejected (wrong size, missing or misplaced indicia), routes picked by gut instead of data, campaigns judged after one mailing, and offers nobody has a reason to act on. Every one of them is avoidable, and we catch most of them at the quote stage. Here are the ten we see most, in the order they tend to happen.
Last updated: June 2026. Rules referenced from the official USPS EDDM documentation.
Mistakes That Get a Mailing Rejected
1. Printing a size that doesn't qualify
The most expensive mistake in EDDM, because you discover it at the Post Office counter after the printing is paid for. EDDM only accepts USPS flats, and the trap is that normal-looking postcard sizes fail the test: a standard 4" × 6" is letter-sized, and the classic 6" × 9" misses by a quarter inch. Plenty of printers will happily sell you either one. The full dimension rules, with the trap sizes called out, are in the size requirements chapter; the short version is that 6.5" × 9" is the safe entry size and bigger is usually better.
2. Getting the indicia or address block wrong
Every EDDM piece needs the five-line EDDM Retail indicia and the "Local Postal Customer" address block, and the whole label has to sit on the top half of the address side. The misses we catch: no indicia at all (the designer left a blank corner), the address block placed lower-right letter-style, "ECRWSS" missing from a hand-typed indicia, and friendly rewrites like "Dear Neighbor" that void the approved format. The indicia chapter shows the exact format; we also place the panel free on every job we print.
3. Sloppy bundling and paperwork
Bundles of 50 to 100 pieces, none taller than 6", one facing slip per bundle, and the printed forms from the USPS tool. A perfect mailing with one slip for the whole job stalls at the counter. The bundling chapter walks the whole drop-off; or skip the counter entirely and let us run it.
Mistakes in Route Selection
4. Picking routes by map shape instead of data
The USPS tool shows household income, age, and household size for every route, and most people never sort by them. A route that "looks close" can be a poor income or age fit for your offer. Two minutes of sorting the table beats an hour of squinting at the map; the carrier-route chapter shows exactly which columns to use.
5. Ignoring the business counts
Every route lists residential and business delivery counts separately. Skip the check and hundreds of pieces land in office mailrooms while you thought you were reaching kitchens. If you sell to homeowners, trim the business-heavy routes; if you need to skip businesses entirely, that's a BMEU option covered in the Retail vs. BMEU chapter.
6. Spreading the budget across too many routes
Twenty routes hit once almost always loses to the seven best routes hit three times on the same budget. Saturation works through familiarity, and familiarity takes repetition. This is the single most common strategic mistake we talk clients out of; the math is in the frequency chapter.
Mistakes in the Campaign Itself
7. Mailing a piece with no offer and no deadline
A pretty card that says "we exist" gives nobody a reason to act this week. The pieces that produce calls carry a specific offer, a deadline, and one clear next step. Invest in the offer before you invest in extra routes.
8. Designing it to look like junk mail
Thin paper, cluttered layout, six fonts, no white space: residents sort mail over the recycling bin, and your piece gets about two seconds to earn a second look. Heavy stock, one strong image, and a readable headline survive the sort. (Good design is also where the oversized formats earn their keep: an 8.5" × 11" physically cannot hide behind envelopes.)
9. Judging the campaign after week one
Mail has a long tail. Menus get pinned to fridges; service cards surface when the AC dies. Reading results after seven days undercounts every campaign, and quitting after one quiet wave is the expensive version of the same mistake. Give each wave a few weeks, and judge the program after a full sequence.
10. Not tracking responses at all
Without a trackable handle you'll never know what worked. A dedicated phone number, a QR code, a coupon code, or a plain "mention this card" line turns gut feel into math. Pick one before the artwork is final, not after the mailing lands.
The 10 Mistakes, One Table
| Mistake | The fix | Chapter |
|---|---|---|
| Non-qualifying size (the 6×9 trap) | Size-check before printing; 6.5" × 9" minimum | Size requirements |
| Indicia/address block errors | Use the approved five-line format, top half of the piece | Indicia & addressing |
| Bundling/paperwork misses | 50–100 per bundle, slip on every bundle, bring the forms | Bundling & drop-off |
| Routes picked by map shape | Sort by income, age, household size | Carrier routes |
| Business counts ignored | Check residential vs. business per route | Carrier routes |
| Budget spread too thin | Fewer routes, more waves | Frequency |
| No offer, no deadline | Specific offer + deadline + one next step | — |
| Junk-mail design | Heavy stock, one image, readable headline | — |
| Judged after week one | Read results in weeks, judge after a full sequence | Is EDDM worth it? |
| No response tracking | Phone number, QR code, or coupon code per wave | Is EDDM worth it? |
The cheapest mistake is the one caught before printing. Send us your piece, your routes, or just your plan, and we'll flag every item on this list at no charge as part of an EDDM quote. Postage is always a pass-through: you pay exactly what USPS charges.
EDDM Mistakes FAQ
What happens if my EDDM piece is the wrong size?
The Post Office refuses the mailing at acceptance, after printing is paid for. There's no fixing a wrong-size piece at the counter; it reprints or it doesn't mail. This is why we size-check every EDDM file before it touches a press.
What is the biggest EDDM design mistake?
Designing for applause instead of action. The piece exists to make one specific offer easy to act on; everything on it should serve that. Second place: putting the address block in the lower right out of letter-mail habit, which violates the top-half rule.
Why didn't my EDDM campaign work?
In our experience the usual suspects, in order: no compelling offer, routes that didn't match the customer, and a single wave judged too early. Geography rarely fails twice; weak offers usually do. Fix the offer first, then re-read the route data, then commit to a sequence.
Can I fix a mistake after dropping the mailing off?
Once USPS accepts the mailing, it delivers. Before the scheduled drop date, Retail orders can be edited or canceled through the USPS tool (online-paid orders refund through Order History). The practical insurance is a pre-flight check before anything prints.
Do you review EDDM files for free?
Yes. Size, indicia, address block, and route plan are checked on every Catdi Printing EDDM job before printing, and we'll review a piece you're planning to print elsewhere as part of a quote. We'd rather catch it than reprint it.
Get a Pre-Flight Check Before You Print
Twenty years of EDDM has shown us every way a campaign can go sideways, and almost all of them are preventable in one review. Start an EDDM quote, see our full EDDM service, or call (713) 882-4629 and walk through your plan with a Houston print rep.