Others add a back-up computer. Once you include the invisible barrier of a decompression-stop in your dive, you should not have to rely on one sole item of equipment. However, entering the water with extra equipment does not in itself make you a technical diver. What is important is the level of theoretical knowledge and ability needed to use the various techniques safely. Divers need to be well-practised in easy conditions until those techniques are second nature.
Some people get their pleasure merely from using equipment.
After all, we buy complicated hi-fi equipment without necessarily knowing much about music, and our cars don't always reflect our driving ability or even our travel requirements. Someone who sees a task to be done, weighs up the requirements, and gathers the equipment and expertise needed to carry out that task. One of the most unfortunate consequences of recent advances in technology was the introduction of the dive computer. In technical diving, which for our present purposes means diving beyond normal recreational depths, the most important skill is planning for decompression stops, for new contingencies and redundancy and for much greater gas consumption. All technical diving training programmes start with a nitrox course in which we learn how to replace with oxygen some of the nitrogen found in the air we breathe.