There is no question that 4×4 vehicles have to put up with some serious punishment. This means that 4×4 accessories need to be able to stand just as much punishment. Any straps should be tough and be virtually impossible to shear through, such as nylon or even Kevlar fibers. They should also be easy to clean; while stains are fine anything more may cause problems later on, either causing premature rotting or damaging scraping. Basic maintenance will keep them usable for a long time.
Of course, make sure that they are of tough materials to begin with so as to ensure longevity. Any latches should be easy to open and close, while any hinges should be of stainless steel or tough plastic. They need to last for a long time, and nothing kills that longevity like a rusted latch or hinge.
With this in mind the accessories should last as long, if not longer, than the vehicle itself.