Deadly force may be used to defend oneself if:

Deadly force may be justified in self-defense when an individual has a reasonable belief that such force is necessary to protect themselves or another person from the imminent and unlawful threat of deadly force from a third party. This principle is rooted in the idea that individuals have the right to defend themselves against immediate threats to their lives or bodily integrity. The key aspect of this justification is the necessity and immediacy of the threat; the person must genuinely believe that their life or the life of another is at imminent risk.

In the context of this question, while options regarding breaking and entering or protecting property may invoke the use of force, the justification for using deadly force is typically more stringent and is generally reserved for situations involving threats to life. Therefore, the legally sound approach is that deadly force is primarily justified in situations where there is a direct threat to a person's life rather than for property protection alone. This understanding aligns with legal standards in many jurisdictions, emphasizing the necessity of the imminent threat for the use of deadly force.