You are dealing with a fish with an average lifespan in the wild of about 5yrs....NOT taking into account the impact that C&R has on that lifespan, how many times a particular fish is caught....and how long a fish's brain can actually retain reasoned thought. All very interesting topics for discussion on their own accord. So basically a fly created 5 yrs ago that was the HOT fly then but is seldom used now is a new fly for the vast amounts of fish today.

In heavilly fished areas, I would say I can see how it could be a problem....but really only when it pertains to the "not new flies" which are generally "new" flies that for some reason or another seem to trigger more strikes. Especially in tourist beats on stretches of some streams that see a HUGE influx of fisherman each season, and a huge amount of folks are fishing those same new flies from the local shops. "Trigger flies" come and go year to year without rhymn or reason really....hot one year, and dead the next. That's always been the case.

My thoughts would be more in the lines that heavy pressure causes fish to be more "skittish" when feeding rather than "selective".