IDPA is not even close to defensive shooting. It's a game. That means it's okay for practicing certain skillsets, but that's about it. The pistols used aren't necessarily what you'd carry, and neither is the carry gear. The targets are stationary, and aren't trying to kill you.

If you're looking to practice, try dry-firing from concealment at home. At the range, practice smooth operation, reloading from mag carriers and such. You don't have to be fast--just smooth. Slow and sure is a lot faster than hurried and fumbling. And practice shooting a bit faster, on a larger target. If you're shooting bullseye, you're already capable of precise application of the fundamentals.