Hi,
I tie up a lot of different patterns and try to fish them all. Often, I'll just tie up one or two before fishing them to see how they work out for me. Slowly, as I get familiear with different fishing locations I'm figuring out what flies work best for different waters (at least, work best for me). I like to fish different patterns just to see what else works. Sometimes, I'll switch flies after every fish caught, and tell myself I have to fish this new fly until I get at least a strike.
- Jeff
P.S. Does one count things like "partridge and orange" vs "woodcock and orange" different patterns? I would call them different patterns (so take that into consideration when reading the above), though I would say they are both the same style of fly (spiders, or soft hackles).