Go check out Josh Rickards confidece pattern section on his website Rocky mountan fly fisher.
I heeded his advice and it helped get me to the answer of the question you just asked. I used to have 3 fly boxes, now I still have three fly boxes but they are more organized with more of a purpose. As Ard said part of the fun is having /tying / trying the stuff. Instead of having 4 patterns you know nothing about have 4 size /color / bead variations of a Barr Emerger.
1) Loaded with the flies you mention in different sizes and variation. Tons of BWO,Adams, Caddis dries. Tons of copper johns, PT, Hares Ear, Barr Emerger,Prince Nymphs in different sizes/colors, RS2,midges. This box goes with me everywhere
2) Big attractor box, Stimulators, San juan worms, Hoppers, Ants, Huge caddis dries, Stonefly patterns. This is for pretty much summer time May-Jul
3) Box of streamers and salmonfly patterns....only comes out for certain rivers at certain times of the year.
One final confession, I do have a little tin full of Trico's that I bring out once a year when I head on a 3hr drive to fish a stretch of river that has an epic trico hatch in early September