I’ve been disappointed with garden hose washers (rubber gaskets). They don’t seem to seal well or last very long. I tried a Buna-N O-ring, from an auto parts store. It works well if I don’t over-tighten the hose.
I think the more flexible O-ring material creates a better seal, and the material seems to last longer. I haven’t replaced an O-ring in seven years.
Portales, New Mexico