I tie flies often and I build rods from time to time. I started fly fishing in the beginning of the 90ies of the last century. Yes, I am that old (45 at the time of writing). I travel very frequently to fly fish around Europe. In the last years I caught trout in Germany, Denmark, Sweden, Andorra, Austria, Slovenia, Poland and Bosnia and was fortunate enough to hook up with trout from sea level to 2400 meters a.s.l. All that with very simple flies. As long as the pattern suggest food in the right size with the right (= often no) movement in the right depth, it will get the job done. If you didn't spook the fish in the first place, of course.
Cool, that you read my blog. I really appreciate it!