As age increases, I think a large part of it has to do with degree of difficulty. As much as Washington State's politics infuriate me I have never lived anywhere with more convenient shooting opportunities. Here on the Olympic Peninsula I have an indoor range 25 minutes away, a trap range 15 minutes away, and another trap/rifle/pistol range 45 minutes away. I know I now suffer more than ever from personal inertial dampenation (PID) but I still shoot about three times a week. And, it's a good thing because if medical issues, doctor appointments or life in general keep me from shooting for a month I can see it in my shooting comfort level. Maybe my muscle memory is trying to parallel my regular memory...   Anyway, I need to keep track of my current skill level rather than trusting my memory to tell me what I can and can't still do.