I always shoot revolver for IDPA (going this Saturday, in fact). I carry three speed loaders on my belt, and one in hand to "load and make ready."
I have 9 speedloaders (for ICORE) so I bring them all to my IDPA matches. It's nice to have extra so you can reload the ones you just used at your convenience, rather than rushing to be ready for the next stage.
I'm curious what revolver you're gong to (or did) shoot.