In the Store: Beware of wheeled luggage under $100. Below that amount, most luggage won't hold up to frequent, rough travel.
Zippers on the main compartment should be big and burly to withstand regular use and take overstuffed loads.
Check fasteners: Parts with screws can easily be replaced, while rivets require more labor.
Fancy handles with lots of parts mean more chance of breakage.
In the Field: If your bag gets spritzed with corrosive salt water, clean it immediately with freshwater.
For grime, a brush and mild nonphosphate soap will do.
At Home: Inspect wheels and other moving parts before heading out. If something's loose, tighten it or have it fixed. Don't let fabric holes go unattendedthey'll grow and even split.