Re: Weapon.
The objective is to never have to go to guns.
Train for the worst, and hope for the best. So we train with other tools (weapons) which include guns, or we are supposed to anyway...
Strategy & Tactics in regard to Apartments, Condo's, and Duplexes have been discussed numerous times around here, so I suggest a search.
The earlier one picks up a signal the more distance they have to deal with a situation.
Distance is not just feet and yards, distance includes time.
Prevention is a key, and apartment keys have been discussed. So has peep holes, and not advertising one has valuables of interest, such as stickers on vehicles, and going to and from one's vehicle with "logo gun gear".
If allowed, install an alarm, get a dawg, or both.
The objective is to not look like prey, this "distances" you from predators. If predators get interested, then alarms, dawgs, or both might distance one as well, as...there is easier prey to be had.
Matters go to serious, then the arrangement of furniture for shooting lanes and cover come into play.
Guns are fine and dandy, and one should have guns , amongst others tools in the toolbox.
No tool is every better than the user of said tool, therefore one must be very good with the tools in the tool box they do have.
Like air horns.
I do suggest you wear ear protection when you mess with that tool...*smile*