Hello all!
I have a hard time writing with a consistent style. My letters often
change shape or size. I'll write one S and then I'll write another S
later and it will look completely different.
This isn't dysgraphia. My writing is legible, and as far as I know,
dysgraphia means you have illegible handwriting. It's just that the
shape/size of my letters seem to change every time I write, and I have
a very hard time writing neatly. What I produce is readable but
sloppy. I've always had somewhat sloppy writing, but in the last four
years (roughly) it seems to have gotten worse, and what concerns me is
that I don't write letters the same way each time. (I'm 22 now).

I realize this question is vague. My theory is that it has something
to do with my memory (I tend to have poor but functional memory). What
I'm asking for is, at least, a list of potential causes for poor
handwriting, if such information is out there.

I've Googled this and come up with nothing. Any help would be much appreciated!

Are you left-handed or right-handed?

So who needs handwriting anymore?

Maybe 'poor' handwriting comes either from a lack of practice or as
evidence that you should consider becoming a doctor.

If you have Attention Deficit Disorder, hard-to-read hardwriting is
confirmed to be an effect of that disorder. Perhaps it can also
explain very inconsistent handwriting. I experience difficulty
maintaining legible handwriting myself.

Or you can look at it in the other way, that this might be a common or
acceptable phenomenon, and only you might be perceiving as something
to worry about.

amber00 - right-handed.

probonopublico - Lack of practice is possible, but I've kept the cash
book (by hand) at my job for about two years. My numbers still look
different each time I write. Sloppy writing wouldn't bother me, but
the inconsistency does, because it could hint at a bigger problem
(procedural memory?)

techtor - I couldn't rule out ADD, but I've never been screened for
it. It's possible I'm worrying about nothing, but there has to be some
physiological reason for it... so I'm just fishing for any research or
articles on it.

Thanks for the comments.

(I like the doctor idea)

Are you a very artistic person? 
Have you ever heard people comment on a peice of art, saying they can
see he artist's mood, or that there is alot of feeling in a peice?
Well writting is, afterall, drawing the shapes of the letters, and how
you feel about what you are writting will affect it.
Perhaps you should forget about becomming a doctor, and think about
becomming an artist.

jenilocke - Very interesting point. I haven't considered the feeling
involved when I write. I think my writing problems become the worst
when I'm pressured or stressed, so maybe it does depend on feelings.
Thanks for giving me something to think about.