What of your neighbors?
In defense strategy you never want the full force of the enemy at your doorstep. Not only self-defense but national defense.
It is actually called,
deep defence or elastic defence a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.
Rather than defeating an attacker with a single, strong defensive line, defence in depth relies on the tendency of an attack to lose momentum over time or as it covers a larger area.
This for a home could be things like a fence, locks, dogs, lights, alarms, etc that may deter or slow down the enemy giving you time to plan your defense or put your plans in motion.
For a nation we have to do the same for our borders. Just speaking of missiles alone, it would be better to have a defense before they fly over the border.