For external data that the diver should know, the assistance of a diving computer is essential. The diving computer provides information on the amount of time needed for decompression and even the depth of the dive itself. It also gauges data such as the levels of nitrogen content in the bloodstream, or decompression sickness that could be fatal to the diver's life.

It would be wise to compare brands of diving computers before actually making a purchase. Aside from considering factors such as cost, quality and accuracy of the machine should also be weighed out. One effective way of doing this would be to search for reviews of the products and gather consensus of those who have bought and used it in their dives.

After buying one's personal choice it would be prudent to study and understand the features and commands of the equipment. It should be known by heart, in the same way that a beginner is trained to deal with various situations that can happen to him under water. To get used to operating the product, it would be advisable to use its functions little be little in short-term expeditions.

Various unforeseen accidents can occur to a diver, especially when he is underwater. One trick is not to panic and to remain calm. Fear is a diver's greatest enemy since it can blur out good judgment and training. Besides, another aspect that should be checked from time to time is the relaxed breathing of the diver. Panic can cause hyperventilation or worse, rapid ascent towards the surface can cause bubbles to form in the body's tissues that could cause lack of sensation, immobility, or death.