Yes pretty much so. I highly recommend the small paperback Art Flicks streamside guide. It focuses primarily on mayflies on the Shoharie in NY. It compares rather favorably with flies in most NEPA streams albeit a week or two later.
The take away is that there are about 10 different major may fly hatches to contend with and they hatch in a fairly consistent sequence. Depending on where you fish you can probably whittle that down to 7 or so. You add a stonefly or 2 and 3 or four caddis you are talking roughly a dozen major hatches. Briefly what I carry is as follows.
1. I don't really fish dries until about May. So I don't carry any early bug imitations. Eliminates blue quill, Quill Gordon and early brown stone.
2. First surface activity of significance is Hendrickson and Red Quill. Start with sizes 14 and 16 and adjust sizes from there depending where you fish. A grey soft hackle or peacock and brown soft hackle will cover emergers.
3.dont really see many grey fox and if I do a small light Cahill will do.
4. Mid May March Browns are a great hatch on most streams, size 12 always seemed to work fine. The wet fly version is also very good.
5. Mid may is also Mother's day caddis. A Henryville special and a grouse and green soft hackle cover your bases.
6. By the end of May look for sulfurs. Mostly yellow size 16 or 18. I find the emerger or comparadun style flies best.
7. Caddis flies are starting to show in significant numbers now too. Tan 14 and 16, and apple ((light green with tan wings) 16 are your best two.
8. June is Isonychia time. Size 10 and 12 comparaduns are my favorites. Also Light Cahills 14 and 16.
9if it's June and fish are surface feeding and you don't see any hatches, try a grey or black caddis size 18
10 BWO comes off all year keep a few handy 12, 14, 16.
11.lastly I carry 4 attractor style flies. In order of preference.
A. Royal wulff 12 and 14
B. Adams 14 and 16
C. Chartreuse adams 14 and 16
D. Orange stimulator. Size 10.
That is pretty much it. If you nymph add a hares ear 14 and 16; pheasant tail 14 and 16; Prince 12, 14,; frenchie 14 16,; rainbow warior 16 and a few perdigons.
Not bogged down with alot of ffliesand you have 90+ percent of your bases covered.
Like anything else, the last 10% is the toughest. To me carrying all that other stuff and gimmicks just isnt worth the expense or time to tie up.