I couple and uncouple air fittings about a hundred times a day in my shop. I have not found a coupler that last longer than another. They all wear out. Both ends. I have to replace them about every year or so. Even the ones on the tools wear out. I haven't wanted to go to the expense of going to a different style. (I use "M" style in NAPA brand IIRC.) I thought about going to the longer fittings. I have heard that part of the reason they wear out is the side load. The longer "nosed" ones go into the coupler deeper and it's supposed to help. IDK. Long winded, but what I'm trying to say is..... just replace both ends and it will stop....... for a while.
For those of you who may not know, there are about 6-8 different "styles" of quick couplers. They are not all interchangable.