Before firearms our first line of defense is hardening the target (our home), training and awareness of our home's layout and how to use it to your advantage.
We had a big concern about home invasion, i.e. esp. waking up in bed to guns pointed at us, so we had our home "gamed" by some professionals (SWAT types) with whom we happen to be close friends. The first thing they showed us was just how vulnerable to having our front door kicked in we really were. Using a stop watch we estimated it would be about 5 seconds to kick the front door and be up to our bedroom. As all the doors in the house were the hollow core variety it's about 1 second to kick those.
The main theme they taught us was to be able to buy time enough to arm, escape, or shelter in place to get or call for help. In all cases the recommendation was that shooting was the last resort. The team leader said if you can get even 30 seconds to prepare you've basically won. With the changes we made to our home it is our estimate that an intruder will not get to us in under 30 or maybe even 60 seconds, depending on where we are. We'll also know where an intruder can go and where he can't (at least not quickly) if he happens to get in.
Without getting into too many specifics here's more or less what we did:
- Installed a bullet proof security system. (We did not want a dog at all.) At least we'll be woken up if an intruder gets in somehow, we'll know if we've been breached if we're away and we won't come home to something in progress.
- Strengthened frames and hardware for all exterior doors
- Added security storm doors
- Ripped out select interior doors and replaced them with steel doors with steel frames. This really affects where an intruder can go in your home. WE know this, the intruder doesn't. It's a huge advantage and it simply buys you time if an intruder has to get through 2 steel doors to get to you. Heck, by the time an intruder gets through 2 or more doors we could actually be out of the house, tables totally turned.
- Moved communications from downstairs to upstairs
- Got educated on our lanes/tunnels of defense and how to use them
- Learned how to sweep the rooms of our house
- Acquired 2nd story ladders in case we had to exit from the 2nd floor. Practice this. It's not as easy as you might think. (This is a good idea for fire anyway)
- Have secondary communications available (walkies) in case it's needed.
We have no illusions. None of this makes us an expert - we've been schooled on one building - our house. No plan survives about the first minute of a conflict. However, by taking the above steps and more we THINK we've eliminated many of the common scenarios.
Oh yeah one final thing and this was something I never thought of. We were told that if you think your guns are loud at the range just try firing in a hallway and then see what happens to your hearing. They recommended to have some kind of hearing protection as they do in their jobs, IF POSSIBLE. So, spend those 30 seconds wisely.
Next on the list is maybe some sort of night vision capability.
EDIT: LOL I forgot to mention the firearms we would use first if it came to that. Me: Benelli M4 loaded with Winchester PDX. Mrs: Beretta 92FS in 9mm. We have others too but those would be the ones we'd grab first.