Newbie Question: How many fly sizes & colors to tie for next season?

As some of you already know, this is my first season of fly fishing.
I tie my own flies so I'm beginning to put together a list of flies to
tie over the winter, for next season. So far I have a list of 25
patterns that I'd like to fish next year. This is a lot compared with
what I tied for my first season this year (I had about 10 patterns
that a local fisherman recommended for my area, and they were very
effective for me). For this past season, I tied roughly two sizes and
two colors of most of these patterns, and tried to tie 6-12 of each
variation.

I realize this is a general question and that patterns may vary the
answer - but - in general, how many sizes of a given pattern should I
tie? An example would be an adult midge pattern in sizes 20-28 or a
given nymph in sizes 16 to 28 -- how many sizes would be adequate to
populate my boxes for the season? I did the math and about stroked
out at the number of flies I would have to tie to do ALL of the sizes
for ALL of the 25 flies. Especially since I am a slow tier at this
point in my experience .... I think I'd die of old age before I got em
all tied :-)

Thanks in advance for any help that you can give me on this.

- Dave K.