geetarman, what most folks do that often doesn't keep the reticule in sharp focus is twofold.
First, one needs to back the eyepiece out just 1/3 turn at a time then look at some distant point at least 200 yard away to let your aiming eye focus at infinity. Then look into the scope with it pointed at a clear sky. If the reticule ain't tack sharp immediately, quit looking through the scope. Continued staring through an out of focus eyepiece makes the eye try to focus; eye strain't not good for sharp vision. Readjust the eyepiece then refocus your aiming eye at a distant target. Finally look again into the eyepiece. Again, the reticule should be sharp instantly. Repeat if needed.
Second, the most common problem with some folks not seeing the reticule sharp all the time is the eyepiece wasn't focused right to begin with. They eye's trying to get sharp focus and older one have a harder time with it.
But sometimes, old eyes just don't stay focused that well, sad but true.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master