Silicone spray will help.

It’s not a perfect seal, but a good spray of silicone lubricant on the hinges and wheels before a beach trip will keep sand from sticking and grinding in. Sand loves dry plastic. A thin silicone film fills the tiny gaps and makes it much harder for grains to embed. It also keeps things moving smoother.

After the trip, blow the hinges and wheels out with compressed air or a strong blast from a hose. Then reapply the silicone. Do this every few trips.

A three-dollar can of silicone spray (or a bike chain lubricant that’s silicone-based) is cheaper than replacing a busted cooler hinge.