While I might be new to this forum, I find something that seems to regularly resurface that can be very advantageous for home defense applications that I almost never see discussed, weather your home or it's your wife / kids home alone. Concentric rings of security. It seems to me the common idea is to have multiple fire arms in multiple locations you can access depending on where you are, have your spose trained as well etc. which is great and certainly a part of an effective implementation, but in my observations it's not enough.
Everything is ultimately about buying time and there are many effective means that add to and further enable the defensive use of fire arms. Body armor for example buys you time to get medical attention (although I think it's unlikely you would have time to don armor during a home invasion) after taking a hit, fire arms and the requisite training buy you more time to live on this earth and possibly for others as well by taking away an enemy combatant's time to harm you / loved ones.
What about increasing reaction time by hardening one's home in ways most commercial or military base buildings use? Certainly there's a cost component, perhaps that's why, but with all the money spent on many different fire arms, perhaps one or two fewer guns with more barriers would be an ideal balance?
1. Security film (e.g. 3M Ultra S800 or others like it) on easy entry windows or patio sliders - it's not bullet proof, it's not impenetrable, but it's MUCH harder to break down than glass when you get a high end grade of it.
2. Reinforced kick plates, hinges and door frame wraps (various brands) on any and all exterior doors. The system I use has plates / 3" long screws on the two lower hinges, wraps for both dead bolt and hand locks and a 3 foot long kick plate screwed into the frame of the house (studs). I had an LE in my home at one point to talk to my adopted son (behavioral issues) and he noticed that when he walked in, we got to talking etc.
3. Have a room(s) in the house with a solid core wood door as an alamo, last stand should an agressor get inside the home or a family member fail to utilize the physical barriers (aka forgets to lock a door).
4. Alarm system, it's information, lots of brands out there, some service based systems will automatically call law enforcement after 60 seconds if the disarm code is not put in (which is good, because even if you can get to a gun, I doubt most people keep multiple cell phones around the house).
I have personally implemented #'s 1,2 and 4 thus far in conjunction with some of the other strategies (to varying degrees, as I have small children, everything I have must at least be in a keypad or bio safe). Think about it, the biggest thing you can do is give yourself time to think. OODA loop. You are the weapon and part of being an effective weapon is intelligence / planning / fore though.
Even the most adept people make mistakes when pushed for time they would otherwise not have made. Training only accounts for pre-determined actions (e.g. muscle memory types of actions), if situations arise that are difficult to train for or have not even been considered, then time to consider is you next best ally. Shooting is a thinking man's game as the saying goes. More time to think gives you an advantage.
The more time you or loved ones have to react, the more likely you will make the most optimal decisions and the more likely said bad guy will give up or be disadvantaged to the point of being defeated. The other great thing is that if I die (say I get into a car accident, leaving my wife and kids), they at least (so long as finances allow) have a home that's hardened against forced entry which buys them time as well, something most homes are not. So I am leaving them with a secure place to live. Sure, they could forget to lock the doors, make a bad choice to let someone in they shouldn't have etc. There's always ways systems can fail, but it's about stacking odds (within reason).
I rarely if ever see these things discussed in regards to home defense or SHTF scenarios, yet they are just as valuable as your training and fire arms. In many cases, would be home invaders will give up if they encounter unexpectedly high levels of difficulty of entry (deny). Do a search for security film foils criminals on youtube, there's a lot of examples caught on commercial building cameras where businesses have implemented this strategy successfully. One instance was actually humorous, the would be thief was so pissed off trying to break the glass, he actually stayed long enough for LE's to arrive and walk up behind him...
The installer of my own security film said most of his work is on military bases as part of base security of their complex buildings with ground level windows and glass doors. They certainly have reasonable levels of security and if you have the means, it's a great tool to augment fire arms and training. Home Defense or SHTF.