SIDEMOUNT FOR RECREATIONAL DIVERS:
Yes Sidemount started with the Cave diver, but you do not have to be a tech or cave diver to be able to dive on Sidemount. PADI has a Side mount course in which you only carry one cylinder/tank on one of your sides instead of your back.
SIDEMOUNT FOR TECHNICAL DIVERS:
The regular Sidemount course you can use for your Advanced Nitrox diving or Cave certifications. The TDI Advanced Sidemount or PADI Tec Sidemount you will use more than 2 tanks while diving Sidemount which can be perfect for Deco and Extended Range. There are even Trimix divers that prefer to dive Sidemount.
SIDEMOUNT DIVING FOR CCR DIVERS:
As a Rebreather CCR diver you will always carry bailouts cylinders with you. Yes you can clip the tank to your side and not think anything more of it, but once you have done a Sidemount course you learn how to properly stage tank to either side and if you are a Trimix CCR Diver even how to stage 3-4 tanks comfortably and safely.
SIDEMOUNT WITH 1 STAGE ONLY:
Stage-only diving is the use of standard deco/stage cylinder configuration, without back-mounted cylinders, on an otherwise standard, or partly modified tec/rec BCD. The lower cylinder is attached to waist D-Rings and the upper cylinder to shoulder D-Rings, both via direct bolt-snap. Some divers (untrained in specific sidemount diving techniques) often incorrectly assume this approach to be sidemount diving. No bungee cord is utilised in the upper attachment, causing the cylinders to hang low beneath the diver and not in line (parallel) with their torso beneath their armpits. Without change of the BCD design, the lack of back-mounted cylinders also causes taco’ing of wing designs and much instability.