There are two basic schools of dedicated dry fly-fishers--those who believe in fishing with attractor flies, and those who choose to try to match the hatch with precise imitations. Both schools have vocal proponents of their philosophies, and, as near as I can tell, both approaches are reasonably successful in catching trout. I guess it boils down to a basic preference of how you want to enjoy your passion.
I personally have always been a hatch matcher--and derive my greatest satisfactions from enticing trout to take my fly when there is a heavy hatch on the water. However, I am quick to admit that there are many times when I have been totally frustrated because the trout were vigorously gulping naturals, and ignoring my offerings. So there is a definite downside to the match the hatch approach to dry fly angling.
Although I prefer to match the hatch, there are many instances when there are no insects present, and it is at those times that I succumb to the use of attractors in hopes of provoking a strike.
I learned long ago that slavish devotion to one’s approach can diminish the fun of the angling enterprise. So, if I prefer to try to match the existing hatch, I am willing to use an attractor when that seems to offer the greatest prospect of hooking a fish. (If that doesn’t work, out come the nymphs).
I also learned another lesson. Instead of trying to have an exact match to an existing hatch, it is usually better to have something just different enough about your fly to have it stand out among the naturals. Often I use a size larger fly than the naturals, and I have found that trout will often leave their feeding lie to take my apparently more appealing offering. Or I may use the same size fly, but have the body of the fly bigger than the naturals. If there is a heavy dun hatch, I may opt for an emerger which the trout may think will be easier to catch than the duns. In any event, I try to come up with something just enough different from the naturals to make it stand out in the crowd. The results have usually proven the value of that decision.
As I think back over my basic approach to fly selection, I see that, although I have a distinct preference (matching the hatch), I endeavor to remain flexible enough to experiment in order to maximize the chances for a successful hook up. And I am certainly not averse to putting on an attractor when that seems appropriate, given the conditions. I guess I really shouldn’t be too surprised at my rather eclectic approach, for I have always been predisposed to be leery of orthodoxy in any form, whether it is in politics, religion, economics…or trout fishing. I hope these observations will prove somewhat useful as you sally forth in pursuit of our finny adversaries.
Good luck!