In Florida (gotta love Florida self-defense laws),
SB-436, the "Castle Doctrine" (Chapter No. 2005-27), establishes 3 critical points:
1. You can use lethal force to defend yourself when in your home or vehicle,
2. There is no "duty to retreat" from any place where you are legally entitled to be, and,
3. Those using force authorized by law cannot be prosecuted for using such force, nor can they be sued by the criminals or family of same for having used such force.
To clarify how 1 and 2 work, the meaning of 1 is that you are allowed to interpret unlawful entry into your home or vehicle as a deadly threat justifying lethal force, and 2 means that you can respond to a deadly threat with lethal force without having to defend against charges that you did not make every attempt possible to flee. Nevertheless, getting ground up into the court system is something to be avoided and even with Castle Doctrine backing you up, it's always better to evade or de-escalate confrontation where possible.