As a diver you rely on your compass for navigation. Without it you often don't know what direction you are swimming in. Asking the locals gets you strange looks or they just swim away. I personally have a suunto wrist compass. We have had a relation ship for a long time but now it is almost over. My Compass has a terminal leak. I noticed that an air bubble has formed and this is the first stage of the decease. At depth it will excrete a little more oil every time I dive until the bubble becomes so big that the part that rotates does not float in the oil anymore and the compass won't tell you your direction anymore. The moral of the story is that if your compass gets an air bubble it is time to replace it.