I've been having an online discussion the last few weeks with fellow guides, fly material manipulators and die hard fly anglers about patterns we all carry. We all have an overstock of tiny BWO patterns in our boxes due to a dismal appearance this past fall. Within those boxes are new patterns we long to use. The fly anglers Achilles heel are flies.
The amount of pattern recipes available for hatches out there right now is simply overwhelming. What's the intrepid hatch matcher to do? We split the difference. Having the picky eater patterns like Lawson's No Hackle and Mathew's Sparkle Duns are always at the ready. Though the more time we spend on the water the more we realize our (unintentional) ability to complicate things. Our first rule in breaking the code is to "turn around and take a forward step". Having the female egg laying, crippled, three legged dun with trailing shuck pattern may not be the fix all.
What works consistently is solid presentation skills combined with a reasonable match of what's happening. We've caught plenty of so called "smart" fish on simple soft hackles during hatches to bring that message home time and again. Kept the rod bent on some storied waters out west with The Usual pattern. Got some strange looks on a spring creek in California when fellow anglers inquired on our fly. A size 18 Royal Wulff was the last thing on their radar.
Stocking both realistic and impressionistic patterns in your boxes will cover the needs of most waters. Even the PHD trout on spring creeks. A couple of examples would be having both March Brown Sparkle Duns and Ausable Wullfs to cover the March Brown hatch. Quigley's Spider Midge and some Griffiths Gnat or small H&L Variants for midges. Slate Drake Compara Dun and a Purple Adams when Isonychias show.
The same goes for nymphs. Mercer's Hellgramite and a few brown rubber leg wooly buggers will cover those bad boys nicely. Craven's JuJu Baetis and the Pheasant Tail Nymph are money on any given bwo event.
Than again you could just emulate the Zen master/angler Sylvester Nemes and just fish soft hackles and not worry about this whole hatch matching thing.