As you've already learned, several options are available for alternate air sources, weight systems, and BCs. For this reason, it's important to review your equipment with your buddy to ensure your buddy knows how to operate it in the event of an emergency.

Identify your alternate air source, and review the procedures to use in the event of an out-of-air emergency. The procedure you use depends on whether you have an octopus, integrated air source, or redundant scuba system.

Review the procedures for removing your weight system. If you have a weight integrated BCD, review the procedure for ditching those weights.

Make sure your buddy knows the location of your BCD's air dumps, as well as quick-release buckles to use in the event the BCD needs to be removed in an emergency.