Defending your home from attack breaks down into two basic complimentary parts: active defense and passive ones. Active defense is taking up arms in defense of your home and passive is everything you do to make your home hard to break into. While no passive defense is perfect, they can help you with your active defense in slowing down attackers and channeling their actions, making it easier for you to defend your home.
Care must be taken here, as your actions must follow the legal definition of self-defense. Even in the worst of TEOTWAWKI events, chances are that things will return to some semblance of normal. When that happens, those who defend themselves may be brought before the bar of justice. In that case, shooting someone two blocks away probably wouldn’t be seen as an act of self-defense.
By and large, the attacker needs to be in your home, for the courts to consider it self-defense. However, in the case of someone actually in the act of trying to breach your door or your home coming under attack from a gang of people, the courts would probably (not certainly) side with you as defending your home.
Having a clear perimeter, such as s fence that is hard to get over or a strong hedge can help you in this, as it makes it clear where your property line is. While someone in your front yard isn’t necessarily attacking your home, they can’t say they didn’t know they were on your property.
I prefer hedges for this, because when properly done, they are even harder to get over or through than a fence. Using a plant that has thorns and intertwining the branches between the bushes can make for an all but impermeable barrier, especially if it is four feet high or so. Just make sure there’s no way for them to work their way around the ends; run the hedge past whatever fence or other barrier might be there.
With the hedge or fence being difficult to get over or through, most people will go for the obvious and try to come through the front gate. That’s actually what you want, as it prevents them from coming onto your property without you knowing it. A simple trip wire alarm will let you know when they come in.
That does something else for you too; it gives you an excellent opportunity for an ambush. By coming in the front gate, they will be coming directly to your front door. That puts them in front of a lot of windows, otherwise known as firing positions. Once they are on your property, their intentions will become clear.
I’d still wait to fire until they take some sort of violent action against you, such as shooting at the house or trying to break in. If you’ve properly hardened your door and windows, they shouldn’t be able to break in very easily. But in trying, they make their intentions clear. Warn them off first, but if they don’t take that warning, then you are probably in for a fight. It can then be assumed that anyone who came in the gate, as part of that group, is there to attack your home.