Start close then shoot further. 15 yards, 25, 30.....
If you get too into you may fall into hunting. I love to shoot. So going out into the woods and poppin squirrels or rabbits is fun to me. But then again I'll eat them too.
Personal defense is really subjective. What's good for me may not be good for anyone else. I generally carry a full sized .40 my magazine has 15 Rd plus one in the chamber. So if I hit you with ab fmj+ hollow point or a steel game and target round or anything else I look at it like
yea the holes are going to be different but within a distance of 15yards to the person getting shot it's not going to matter. I have some Winchester game and target loads in one magazine and some herters critical defense rounds in another mag. I keep mags all over the crib so when I'm ready to go I pop it in and go. And when I come I side and unload sometimes I'll end up with two mags on the main floor or upstairs so they get moved around a lot.
"You'll want ammo that's not going to go through 1-3 walls in the house potentially killing your own family" that's a good rationale but the reality is you should know you house better than an intruder and youve got to navigate and manage situations to where you're in control.
My opinion is that whether someone shoots a deer slug at you or birdshot if it makes contact especially as a home intruder your ass is going to be looking for the nearest exit if not trying to make one through the wall like a cartoon character. You aren't going to get shyt and evaluate "is this birdshot, 00, #5, #7, was that a deer slug? Hollow point, fmj, plastic or steel...etc.
Now the defining factor and what people consider most is will the ammo be enough to stop the threat or action. Honestly birdshot isnt going to stop a 6'3 240lb man who is drunk or high and / or pissed off from stabbing your daughter or wife, or son and unless the shot is perfect it wouldn't stop him if he were charging at you.
In my life I'm more likely to have someone in my garage or stupid enough to make entry to my house with the intention to steal rather than harm me or my family.
I know what I need to do to protect myself and family but other people are going to have different needs. I don't carry a spare mag because I have 15 rds. I know people who carry 7+1 and keep two 7 Rd mags. Thats 22 bullets ...I dont need all of that. But that's them and I'm me.