What are the controls and conditions for applying the principle of committing the lesser of two evils, and is it permissible for the general public to apply it?

The rule is sound and valid, and its purport is that when benefits and harms converge, one should strive to achieve the benefits and ward off the harms. If that is not possible, then priorities are considered. If the harm is greater than the benefit, the harm is averted. If the benefit is greater than the harm, the benefit is pursued, while bearing the harm. However, if they are equal, one may choose or pause.

Conditions for benefits: They must be aligned with the objectives of Islamic law, reasonable in themselves, and pursued for the preservation of a necessity or the removal of hardship.

The determination of legitimate benefits is not left to the general public, because deducing rulings from principles is not for everyone.

As for committing minor sins to avoid greater harm, the assessment of harm must be based on Islamic law, not personal desire.