I wasn't paying attention, and it cost me $185 on a recent flight

I picked my jaw up off the floor and blinked in confusion. "One hundred fifty dollars?" I repeated, swallowing hard and handing my credit card to the agent at the desk. I had already paid $35 to check my suitcase, and now I was being told that I would have to fork over another $150.

I was on the second leg of a three-part trip that was taking me on the road for nearly a month -- from a cruise industry conference in Florida to a cruise along the California coast, followed by an expedition sailing in Alaska -- and I had packed accordingly. (After all, hiking boots aren't exactly professional, and business attire isn't practical for glacier trekking.)

With how quickly cruising has restarted over the past year, sailings are added to my calendar months in advance. Flights are booked, and I forget about them until it's time to check in. That's exactly what happened here.

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My flight to Florida was part one of the journey. I was booked with United Airlines, my usual carrier. Because I have Premier Silver status (I'm this close to gold, y'all), checked bags up to 70 pounds are free, so I thought nothing of packing everything I needed.

However, I completely forgot -- until check-in 24 hours prior, when it was too late to adjust my suitcases -- that the second leg of the trip was with JetBlue. (It used to be my preferred airline, so I book a flight with them every once in a while, just to keep earning points.) I paid the initial $35 checked bag fee on the app during check-in, but when I reached the airport and told them I had an overweight bag, they charged me an additional $150.

Call me a naive traveler because, at that moment, I totally was. I figured they'd at least count the $35 I already paid toward the $150. But no such luck.

To make things worse, I had reached out to American Express just two weeks prior to change my preferred airline from JetBlue to United, so I wasn't even able to cover the cost with my $200 annual airline credit via The Platinum Card® from American Express. (Enrollment is required.)

I had never traveled with an overweight bag before, so this was all new to me. I knew, somewhere in the back of my mind, that airlines charge for extra-heavy bags, but I didn't realize some levy fees that are nearly the cost of another flight.

In the grand scheme of things, JetBlue's overweight bag fees are actually not the most expensive. They fall somewhere in the middle, with United charging $200 for bags between 50 and 70 pounds and $400 for up to 100 pounds. Meanwhile, American Airlines will ding you $100 for the former and $200 for the latter. As for Delta, the fees are $100 and $200, respectively, on most flights that allow overweight luggage.

The moral of the story here is that it's easy for things to fall through the cracks. This is especially true when you're someone who travels a lot or if you travel with one airline so frequently that you're used to certain perks you might not be entitled to with other carriers.

The experience prompted me to go through all of my upcoming travel arrangements to make sure I know what I'm in for. Because it was such an expensive mistake, it also gave me the nudge I needed to return to the carry-on-only mentality to which I strictly adhered pre-pandemic.

All in all, it was a reminder I needed, but it was a costly one. Hopefully, my mistake doesn't have to be yours.