Something I just realized I don't understand about the forms API:
I'm putting up a form where I have to do a bit of work to figure out exactly what the form's contents should be (e.g., which of a possible set of radio buttons should, in this specific situation, really be there). This work is getting done not only on the first pass through the _form() handler -- the one that produces the form presented to the user -- but also the other calls to _form() that happen along the way to the form finally being submitted.
So: If I can find some way (down in $form_state, I presume) to figure out which pass through the handler I'm on, can I safely skip these form generation calls? Or will omitting them screw up something else? A few simple attempts (e.g., checking the contents of $form_state['values']) haven't worked; are these multiple calls just part of the price of the forms API? They're not that big a deal, but every little bit helps...
