Suitcases, carry-ons, and other kinds of luggage all have plenty in common. They usually come with wheels, a handle, and zippers. But not all suitcases are created equal and if you don’t do your homework before heading out on your travels, you might find out the differences the hard way.

A better option is to consider the results of our recent survey of luggage satisfaction sent to 65,000 Consumer Reports subscribers. The respondents told us wheelability and durability are among the most important factors to consider when purchasing luggage. In fact, according to more than 27,000 subscribers who rated their suitcase, satisfaction with the durability of the luggage turned out to be the greatest predictor of overall satisfaction.

Here's what to consider when buying luggage.

Wheelability

Most luggage sold today comes with wheels. The challenge is to figure out whether you should buy luggage that comes with four wheels or two. Travelers who prefer four-wheeled suitcases like them because they can spin 360-degrees, making them easy to maneuver. With four wheels, you can easily wheel the luggage besides you, in front of you or behind you. It’s also easy to navigate in airplane aisles and other tight spaces. But there are some downsides: If you find yourself on an incline, that piece of luggage could roll away.

A two-wheeler, on the other hand, goes only forward and backward. It’s less ergonomic than a four-wheel spinner, but if you’re going to be walking along city streets, two-wheelers are better than four-wheelers for clearing curbs and rolling on sidewalks, cobblestone streets, and other uneven surfaces.

Durability

Zero in on the zippers. If a zipper breaks when you’re travelling, it can be a headache. So vet the zippers on your luggage before you buy. Zippers come in two types: chain and coil. The chain zipper has two sets of interlocking teeth, usually made of metal. Chain is better and stronger than the coil zipper, which slides on two parallel coils usually made of polyester. Chain zippers are much more difficult to break into. Coil zippers can be pulled apart with a ballpoint pen. Also, some savvy buyers consider zippers a proxy for the overall quality of the bag—so you may want to take a close look. The zipper brand YKK is widely believed to be the most reliable zipper on the market.

Whirl the wheels. When it comes to durability, wheels can be a weak spot. Check that the wheels roll smoothly and stay in place. Gently jiggle them with your hands to make sure they are firmly attached.

The wheels on four-wheelers are mounted externally, leaving them vulnerable to snapping off with rough handling. For a more secure attachment, check that the wheels are attached with screws, rather than rivets.

A two-wheeler, on the other hand, has recessed wheels, protecting them from snapping off. Also, like the wheels on inline skates, they roll only forward and backward, causing less wear and tear than the 360-degree spinning four-wheelers.


Check our luggage buying guide and our new retailer Ratings to find the best places to buy luggage.
 

Hold the handle. For maximum durability, the handle should have little to no wiggling or rattling as you pull the bag. One that retracts completely inside the bag is less likely to sustain damage. Also, check for smooth movement as you pull it up and retract it.

Select a side: Hard or soft. Like the majority of suitcase owners in our survey, if you want soft-sided luggage because it’s lightweight and allows you to stuff in “just one more” item, make sure it is a high-denier material. (Denier is a measurement of fabric weight.) If your highest priority is protection from rips and protection of your packed items, a hard-sided bag would be better. They can't be torn or intentionally ripped open with a blade. The most durable? Aluminum luggage. But it’s also the heaviest.

Bring a tape measure for carry-on luggage. Ignore tags, labels, or promotions that proclaim, "official carry-on luggage." Nothing is official. No regulation dictates carry-on size—airlines impose their own restrictions, and the limits can vary among airlines and even among aircrafts. Moreover, a 2015 Consumer Reports investigation found that nine out of the 11 models we measured were larger than claimed by the manufacturer.

Bottom line: Measure the dimensions yourself. Make sure the measurements account for all parts, including outer pouches, wheels, and handles. And if you are buying online, check the comments section on a suitcases' model page for any complaints about real versus advertised size.

For more buying tips, including tips on size, warranties, and interior capacity, check our luggage buying guide.