The basic principles of the equipment configuration. We're talking of course about the safe recreational diving- technical diving is administrated by different rules.
What we take for diving equipment depends on the transport (aircraft), air and water temperature, the type of diving, and of course funds.
The general rule of diving equipment configuration is mirrored/ doubled elements necessary for the safety of divers, such as the regulator, buoyancy control systems, measuring devices and lighting. Common sense dictates that the criterion of a minimum set of equipment did not allow us to look like a Christmas tree. In the case of night diving two flashlights and marker light to a minimum. Two sources of air-automatic and octopus is currently standard. The cold water is recommended to two slots of the first stage and the two cylinders, as in deep diving.
More and more divers I use always two independent breathing machines first degree. In the event of a hardware failure, and respiratory systems double assurance partner give a really good margin of safety. The wreck diving- dry suit and jacket are double of the buoyancy control system. A failure of one of them on the wreck of these elements may easily occur. The air services have limited capacity- limited weight equipment. If You a lot travel by airplane, try you buy equipment with low weight. Diving in their own equipment is safer well- it is known configuration. Most important is the jacket- control buoyancy and support for additional hardware is instinctive. The limited field of vision in a mask, a lot of incentives involved for diver- own jacket is instinctive like "body mapping" - instinctively know where the equipment is pinned.
At the end- weather conditions. Tropical wet-suit 3-8 mm with hood, fingerless gloves and special cutting tools (protection of the reef). Cold-water suit, a minimum of 8 mm, preferably dry suit and thermal underwear, lighting and two automatic first degree.