Luggage manufacturers are paying attention to airline mandates and adjusting designs so it's hard for a suitcase these days to flunk the size test at the airport. Weight is another matter, and the best luggage can be heavy, which means you pack less or pay overweight baggage fees. But a burst bag can wreck your trip, so it's a trade-off.

Hardside/Softside
It's a matter of preference. Softside luggage can be light and flexible, but not always waterproof and zippers break. Hardside luggage keeps your clothes dry, but dents and scratches can look a mess after one trip. If it must be hardside, go with polycarbonate---it's durable and light.

Fabric
Denier is a measure of fabric strength, so don't go lower than 600 denier polyester. But a far superior fabric is 1800-2500 micro-ballistic nylon. When comparing fabric denier from two different manufacturers, note that denier is counted differently in the United States and Asia, where a lot of luggage is made. For example, 800 U.S. denier is 1680 Asian, so don't be fooled.

Manufacturers also throw around the term "ballistic" like all luggage is bullet-proof, but it only indicates that the fabric has a special basket weave once used for ballistic nylon, and has nothing to do with strength. Truly ballistic nylon is very expensive.

Nylon is more durable for luggage, but polyester is typically used on inexpensive pieces. You'll also find bags of high-density, canvas-like cotton. It's durable, but not as rip- and tear-resistant as nylon.

Luggage also now comes in a synthetic leather made with a special coating on fabric that's quite durable. Real leather luggage is top of the line, but it's heavy, expensive, requires maintenance to stay supple and doesn't get treated any better than cheap luggage when it's out of your hands.

Look for all exterior corners to be sturdily reinforced.

Wheels
You see few travelers today carrying luggage without wheels. Two wheels are giving way to four spinner wheels that rotate so you can pull or push the bag and it doesn't fall over when standing still. Because any protrusion can break off, the wheels should be recessed into the frame or otherwise protected. The wider the wheels, the better.

Zippers and Handles
Look for zippers made of heavy cloth that's double-stitched on both sides. Telescoping handles should lock up or down, and not protrude when down. Other handles should be securely double-stitched or screwed to the frame. Rivets can pull out. Shoulder straps should be wide and padded.

Weird is Good
Since 90 percent of luggage is black, dare to be different and avoid losing yours, or make it easier to trace. If you find the right bag in an unusual color or pattern you can spot a mile away, grab it.

Tip
Put a fabric softener inside your luggage when storing it to keep it smelling fresh.