Actually Taro seems to be the only character that not only merely accepts his
curse but actively enjoys it and revels in it. he sees it as a blessing. maybe
that's how he kept the curse from locking, he accepted it and then made it a
part of him.

<< Or Four times as fast.  And Ranma's had his curse for what, two or three
 years before it locked up?  Even if Pantyhouse's curse took four times as
 long to lock, he's what, 16 years old?  He should be stuck by then.  I
 recommend that he find some other reason for all the curses to lock up.
 Like maybe the flooding of the springs did it? >>
    Mm.  Or he might have it suggested at some point that Pantyhose -- who
Ranma has, naturally, been looking for unsuccessfully -- might know a way to
unlock the curse.
    Of course, if you continue in this vein, that would open up the
possibility of Ranma and Ryoga locating Pantyhose and asking him.  There are
two ways you can take it -- Pantyhose might know of a cure, or only how to
delay the curse's locking up.
    The cure option is preferable, if you aren't going for spamfic, because,
after all, nobody said getting the cure had to be easy.  Also, it'd be the
perfect opportunity to drag them all over the world several times after
obscure/rare/'impossible' objects...
     "Ranma read some of the ingredients listed on the scroll.  Fresh albino
penguin blood?  Well, at least he had a better chance of getting that the
dinosaur skin thong bikini...whatever purpose that was supposed to serve..."

        --Ryo Hoshi