You just set up your equipment for the first dive of your vacation in Saint Somewhere, as you activate your Sports Flare and the bulb burns out. The worst thing that can happen on a tropical vacation has just happen No back up dive light. Pre-dive equipment preparations are serious business. Missing or broken equipment can ruin an otherwise perfectly planned dive. Just put a replacement bulb in your dive bag so you will have it in case you ever need it. It is always better to have an extra and not need it than need an extra bulb and not have one.