Keep asking away! Most of us are more than happy to answer, and they're good questions, too.
I don't know anybody that practices with the same ammo they carry, assuming that you carry hollow points that run about a buck a shot. I do think that everyone runs at least a box of the ammo they plan to carry through the gun, just to make sure it functions and to see where the point if impact is (POI).
If you have a 9mm for example, ammo will run at about $11 for a box of 50. Defensive hollow points go for $20-30 for a box of 20-25!
Expensive!
I would recommend trying to practice with the same bullet weight as the ammo you plan to carry, your poi should be more similar than if you shoot 115 and carry 147