urbanknight

I don't use the cap because it's inconvenient to unscrew them every time I inflate the tires, and I rarely get a bent valve, but it does happen. As mentioned above, you can just swap the core out. You could even start collecting cores from tubes you're about to throw away, giving you a stash of spares.

These are very useful for when the tube goes completely flat and the pump head tries to push the whole valve inside the rim before engaging fully.