Your largest bag will hold the bulk of your clothing and some or all of your gear. Useful 45-inch carry-on styles (21 or 22 inches in length) include the shoulder bag, the travel pack (convertible backpack), and the wheeled bag. To be able to pack, choose a bag with a three-sided zipper that makes it possible to open it flat like a book.
In choosing a bag, consider:
(a) How you want to carry it (on your shoulders, on your back, or by its own wheels).
(b) How much you will be carrying it (take into account types of transportation and activities).
(c) Terrain and handling conditions (rough? normal? rugged?).
(d) How you want to organize and pack it.
(e) Your long-term traveling needs.
Shoulder bags are suitcases with a handle and a detachable shoulder strap. Semisoft versions have a structured frame created by piping and foam padding that hold the bag’s shape during packing. Their main attraction is ease of organization: they come in one-, two-, and three-compartment designs. They also compress easily to fit into tight spaces. If you are carrying a fully loaded shoulder bag, I recommend taking a luggage cart as well.
Three-compartment bags are the perfect high-capacity all-purpose bag for short trips, extended trips, or trips requiring two wardrobes. Make sure that at least two of the compartments where you will pack clothing open completely. You can stow warm-weather casual clothing in one section, business or cold weather wear in the second, and use the third compartment for your gear. These bags are packing-friendly because each compartment is supported by piping and foam padding and keeps its shape during packing.
Two-section bags are useful for short trips and simple wardrobes. They allow the traveler to separate clothing from accessories or the washed from the unwashed. Additional outside pockets help organize accessories.
People like one-compartment pullman-type bags because they are so easy to pack and a single zipper provides access to all their belongings. Some bags come with a movable partition that converts them into a two-compartment bag. Wheels, a selling point for many travelers, are available only on one-compartment bags.