If you are using your iPad plugged in a lot, and moving it around a lot while plugged in you should look for a thicker cable, one with strain relief after the plug. Usually a bit of plastic extra plastic that is stronger than the cable, but weaker than the plug itself.
Some cables, including earlier Apple cables had a habit of wearing out quickly in these conditions. You could often see the signs of it near the plug.
Braided cables are probably the sturdiest option, but they come with the disadvantage of being a bit stiff. The wear and tear on the cable could end up being replaced by wear and tear on the port, though to a lesser degree. Some of the newer Apple cables seem to be a bit thicker, and sturdier. Many third party cables can be thicker as well. Avoide the cheapest brands. Go with the ones that say they are MiFi Apple certified to be certain, but any decent quality brand should do.
Keep in mind if the cable is being flexed a lot, no cable is going to last forever. A couple of years is actually pretty good for thiner cables. the kind that are easiest to use or pack in your bag.