re: Handgun - Knockdown Power vs Concealment

I have 9mm. It’s a matter of simple economics. I can afford to practice more often with 9mm ammo. I’m not in an occupation where people are out to kill me or I may be attacked by a sniper. At the close distances I figure for self defense the difference is marginal between a 9 and the larger more popular calibers. I put familiarity with my gun and accuracy above kinetic energy.