As I gather things to pack for a very long trip to Antarctica, the weight of each item is on my mind. I have a 50 pound limit for my duffle (which will be checked) and an 11 pound limit for my carry on. On top of that, National Geographic-Linblad has recommendations for what to pack. The packing list conflicts with the weight limits.
Let's take camera gear. They suggest a camera, a laptop to process photos on the trip, and an external hard drive for backup, just in case the camera goes into the Southern Ocean. Those items weigh 9 pounds, and I refuse to check any of them due to high probability of theft. My camera is a "bridge" camera, meaning it is the best I can get without using a more professional model with interchangeable lenses. A pro get up would be 11 pounds or more on its own. Nat Geo is keen to have its travelers take great photos, so I smile at the discrepancy between the weight limit and their suggested equipment list.
What to do? My carry on bag will be a small roller bag, one that I have been able to fit under the seat in front of me on many planes, and small enough to fit in the overhead on the starboard side of an Embraer E-175. I'll have plenty of space on the international flights, but might be in a small plane on the domestic flights I'll take in Buenos Aires and New Zealand. Because no one weighs carry on bags, if I exceed the limit I simply need to act as if the bag is feather light. I'll keep a smile on my face and avoid grunting as I heave the bag into the overhead.
Checked bags are different because they are weighed during the check in process. I am carefully considering each item. My oral health is important to me, so I use mouthwash, floss, interdental brushes, and an electric toothbrush. I learned that mouthwash is not absolutely necessary, even though I prefer to use it. Now that I've weighed the mouthwash, I am ready to jettison it because 8.5 fluid ounces weighs more than 6 packs of hand warmers. When I'm walking on the ice to see the penguins, I'll need to warm my hands much more than I'll need to ensure I don't have bad breath. The stench of penguins overtakes anything, even bad breath due to garlic.