In my neck o' the woods, I believe wings make a difference, so almost all the dries I tie have wings. A very wise flyfisherman friend once postulated "The wing brings 'em up, and the body color takes 'em.", and I agree. I usually fish on heavily-pounded streams...so it isn't so much about the hunk of iron hanging off, but moreso the fishies' trigger being initially twitched because of the wing silhouette (or the body impression on the water if a cripple or emerger in the film). But to clarify, I seldom use duck quills, nor do I use Catskill-type dry flies. I just don't like taking the time for tying those wings. For slower water, I use flies with "comparadun-type" wings. For quicker water, I use "hairwing dun & emerger-type wings". I always use some sort of wing on all my spinner patterns -usually darlon, zelon, or poly. Also of note - - -I fish alot of dry midges... I seldom put wings on flies of size 26 or smaller, even the spinners. BTW, I call everything smaller than a sz. 26 a "B52" (bug, size 52) .

And one last thought...I've fished in sw Montana and sw Colorado for a couple weeks each year for the last 20 or so years, and I don't see wings on emergers, dries and spinners as being that important to the fishies. Not so on the San Juan, though! (that oughta raise some discussion...)

Your mileage may vary...