What does the "50% rule" in diving suggest?

The "50% rule" in diving refers to the guideline suggesting that divers should use half of their tank's air before ascending. This practice is important for ensuring that divers maintain a sufficient air reserve for a safe ascent and any potential safety stops. By adhering to this rule, divers can effectively manage their air supply, minimizing the risk of running out of air during the ascent phase of the dive.

Using half of the tank's air provides a buffer that allows divers to address any unexpected situations that may arise, such as needing to assist a buddy or handling complications while ascending. It reinforces the principle of conservative diving practices to increase safety and enhance the enjoyment of the dive experience.