Shipping eats profit. Quietly, persistently, in ways that don’t show up until someone actually sits down with a spreadsheet and wonders where the margins went.
The weird thing? Most of these mistakes are fixable. Not easy fixes, but fixable. The problem is nobody teaches this stuff.
Sellers figure out sourcing, build a halfway decent website, maybe even crack the code on ads that don’t completely drain the budget. But shipping just kind of… happens. It gets set up once and forgotten.
Here’s what tends to go wrong.
Relying on a Single Carrier for Everything
A seller signs up with one carrier because it’s familiar. USPS, usually. Sometimes UPS. And then that’s it. Every order, same carrier. Doesn’t matter if it’s a tiny envelope going three miles or a heavy box headed cross-country.
But no single carrier wins every scenario. USPS tends to be cheaper for lightweight residential deliveries. UPS and FedEx often make more sense for heavier items or B2B shipments.
For time-sensitive stuff in metro areas, regional Los Angeles couriers or local same-day services can actually undercut overnight rates from the big national players.
Nobody’s saying use five different providers. That’s a headache. But comparing rates across different package profiles quarterly, even just spot-checking, tends to reveal gaps that add up.
Dimensional Weight Surprises
This one’s annoying.
Someone packs a lightweight item in whatever box is lying around. The item weighs two pounds. The box, by dimensional weight math, “weighs” twelve. Guess which number appears on the invoice.
Carriers have done this for years. The formulas aren’t complicated, but they favor the carrier, not the shipper. Smaller boxes, less void fill, right-sized packaging. Basic stuff. But it requires actually measuring common package sizes and comparing against pricing tiers.
Most people skip that step. Shows up in their costs eventually.
Failed Deliveries Add Up Fast
A package that doesn’t arrive the first time costs twice. Sometimes more.
Redelivery fees. Customer service time. Refunds or replacements if the buyer gets frustrated. One estimate floating around puts failed delivery costs at roughly $17 per attempt. For anyone shipping a few hundred packages monthly, that math gets ugly.
The frustrating part is how preventable most failures are. Bad addresses. Nobody home. Apartment buildings with restricted access. Address verification catches some of it. Offering delivery windows or pickup options catches more.
Some sellers switched to local services with real-time tracking and saw failure rates drop just from better recipient communication.
Not a magic fix. But not nothing either.
Carrier Contracts Aren’t Set in Stone
Sellers with consistent volume have leverage. Carriers want that business. But they’re not calling anyone up to offer discounts out of the goodness of their hearts.
Common story on seller forums: someone ships 500 packages a month for two years straight, never thinks to ask for better rates. Finally calls, requests a volume discount, gets 15% off within a week. Money just sitting there the whole time.
Delivery driver employment is projected to grow 8 percent through 2034. Carriers need capacity. Shippers providing steady volume have more room to negotiate than most assume.
Worth a phone call, anyway. Worst case, they say no.
Shipping as Afterthought
Less a specific mistake, more a pattern.
Shipping gets bolted on at the end. Sometimes literally the last thing figured out before launch. But it touches everything: pricing, satisfaction scores, return rates, whether customers come back.
The growth of e-commerce platforms pushed expectations way up. Faster delivery, better tracking, lower costs. That’s baseline now, not bonus.
And the landscape keeps shifting. Recent numbers show Amazon surpassed USPS in total package volume last year. 6.7 billion packages versus 6.6 billion. That’s not a small gap in perception. Customers increasingly expect Amazon-level logistics from everyone.
What Actually Helps?
Paying attention, mostly.
Compare carriers sometimes. Measure package sizes. Track what’s getting delivered versus what’s bouncing back. Ask for discounts. Treat shipping like an actual business function instead of a nuisance to tolerate.
Sellers who do this, the ones who look at data and adjust, tend to have better margins. Not always. But often enough that it’s probably not a coincidence.
