I see no hope for the future of our people if they are dependent on the frivolous youth of today, for certainly all youth are reckless beyond words. --- Hesiod, Eighth Century B.C.
Checkwriter's link is a great one - my only add would be to give your DD a complete break of several weeks to a month twice a year. It allows both physical and mental rest and if she's not chomping at the bit to start up again after a few weeks off, well, you just learned something...
We have always thrown every other day. If there are games on both sat and sun then no pitch on fri or mon just throw tues thurs. Have never believed in everyday and the pitching is only for 30 to 45 min with a good chunk of that just getting loose and ready to really throw hard. DD has not sustained any injuries so far (10 years) and when she is sore from a long weekend minimum 2 days off with lite work to get back into it and a definite 1 month off in between spring and fall and fall and spring. When she was younger it was 2 weeks but now no touching a ball for at least a month. It works for us and she is just fine. It is not a race and I am happy we have not treated like one.