Pack around repeatable outfits, real weather, and what cannot be replaced easily.
Start with the weather, the activities you will actually do, and a small group of clothes that work together. Shoes and bulky just-in-case items consume luggage faster than almost anything else.
The extra weight has a price tag, not just a wrinkle in your dignity. Most U.S. airlines cap checked bags around 50 pounds, and every pound past that gets billed separately, cheerfully, at the counter. Frontier, for example, charges $75 for a bag that lands 41 to 50 pounds and $129 once it crosses into the 51-to-99.99-pound range — a lot to pay for the privilege of packing indecisively. A suitcase padded with two backup outfits and a just-in-case rain jacket is not a packing choice, it is a fee waiting to introduce itself.
Leave room for souvenirs, dirty-clothes organization, and the basic dignity of closing the suitcase without sitting on it.
A bathroom scale at home takes thirty seconds and tells you exactly what the airline's scale will say later, in front of a line of people. Weigh the bag before you leave, not after an agent weighs it for you.
