Hmmm...I voted for the bi-monthly (once every two months), but I'd quickly run out of patterns...I only really tie three freshwater patterns, and one saltwater pattern...hey, that's what works for me...the hard part is figuring out which size and color variation is working
I know of one guy who only fished one pattern and it was dry fly pattern and he actually did pretty good...I think it was a Caddis pattern...but then again, in a moving-water environment, the fish have to eat whatever comes by, or starve...