You will have invested lots of money in expensive dive gear therefore it makes sense to maintain it properly which will give you more personal enjoyment underwater as well as extending its life.
More importantly, it can ensure your personal safety.
After each day of diving, clean, inspect and prepare the regulator for the next use or for storage.
As soon as the first stage is removed from the cylinder, reinstall the dust cap over the regulator inlet port. This cap is normally attached to the regulator yoke and therefore has been under water.
BCD’s are rarely dry and with warmth they soon collect organic matter – which is ideal for bacterial growth. 
After you’ve drained as much of the water as possible inflate the BCD at least halfway and hang it on a BCD hanger to dry out of the sun. Tank air, being 99.9% humidity free, will help dry the bladder inside and prevent mould formation.
Even though they are made of treated steel or aluminium and then painted, you should still take a minute or two to rinse the tanks with some fresh water.
Salt and sand can build up in the valve knob, o-rings can degrade and crack and dirt and grime can collect under the black plastic boots where pitting can damage cylinder’s surfaces and lead to corrosion.
Since you’re rinsing everything else it just makes sense to spray the cylinders down too.
Reduce cylinder and valve damage
Proper handling of a scuba cylinder is important for the longevity of the cylinder itself and for the safety of the diver.
Avoiding scratches, dents, or sudden impacts to the cylinder is necessary to ensure a long service life. External damage can weaken the cylinder, unseat the valve or cause the cylinder to not properly connect with other equipment, namely the first-stage of the regulator harness.
Be sure not to drop your cylinder particularly on the valves. Lie cylinders down whenever unattended and make sure they can’t roll. If possible fit plastic carry handles around cylinder neck.
Cylinders should only be kept upright if they are secured, such as on a dive boat or a dock equipped with cylinder restraints. Whilst resting the tank on its side is best, it is important to make sure the valve area does not get contaminated with dirt or sand.
Prior to assembling the 1st stage to the cylinder, always check the ‘O’ ring is clean and undamaged.
Fins need only to be rinsed in clean, freshwater and dried in the shade.
The best way to store fins is to lie them flat so that the blade is not bent or curled.
Plastic stiffeners placed in the foot pocket can help keep the pocket from collapsing when stored or transported.
The snorkel should be simply rinsed out and checked for any damage.
Latex seals can perish easily.
The main reasons for this are skin oils, perfume in talcum powder, exposure to sun and failing to wash them after usage in the sea and therefore leaving them salty during storage.
If you are going to dry your suit on hangers, it is important that you use an extra wide hanger. If narrow or wood hangers are used, the suit is likely to be damaged due to excessive pressure.
After the suit has dried, the zipper should be left open and lubricated with bees wax or silicone lubricant (non-petroleum based) to make them easier to open and close next time.
As soon as possible, hang up your gear to dry and pack it away dry and clean!
Remember that sunshine isn’t good for dive gear – leaving it laying around in the bright and hot sunshine for long periods of time is bad and can lead to rotting, cracking, and fading of various parts of your kit.
Neoprene rubber is especially affected by ultraviolet light and wetsuits, boots, hoods, gloves etc should not be left out in the sun any longer than is necessary. It is better to roll your neoprene suits once they are dry, folding them for prolonged periods can cause any folds to become permanent. Either hang them or store in the bag that they came with.
BCD bladders, low-pressure inflator hoses, and regulator components can also be affected by prolonged exposure to sunlight.
If you’re not planning on diving for a while or packing your dive gear away for the season making sure things are dry is critical, not only for the gear, but for your health as well!
TIP – Consider using desiccant pouches which will absorb any lingering moisture.
TIP – Cylinders are best stored with some pressure inside to prevent moisture build up.
