I tie all my nymphs and streamers, and usually buy my dries.
I rarely lose a dry, but nymphs and streamers are gonna get hung up pretty often bumping around the stream bed...
Overall though, I've found that I can tie a pretty large array of patterns with a fairly small material selection. You can substitute almost anything in a particular pattern- I find that is half the fun figuring out how to tie a new pattern that calls for materials that I don't have- in essence how can I make this pattern my own version with what I've got? You'll find most of the time you'll be able to figure it out then hone it in after a couple passes. Also, it's super fun to catch a fish on a fly that is tied with "the wrong" materials!