Wise counsel. I have to laugh at myself how easily I fall into the paradigm of at least starting out with the fly that worked last time even though it may be a different season. This last June I got to fish the South Fork of the Rio Grande for a few days. Stonefly nymphs were active. I had to buy the nymphs because I did not have any( very irksome to have to buy flies for a fly tyer.) Had a great trip and caught lots of fishand with a some big ones.
When I got home I tied up a goodly amount of stonefly nymphs that took up a 1/4 of my main trout box. I showed them to one of my local fly fishing fishing buddies. He laughed and said where are you going to use those. He was right because are local trout fisheries are all below reservoirs and we seldom fish any flies over a size 14 often much smaller and stoneflies are not even on the hatch charts. I said well they worked good the last time!