You are asking to yourself what to do to maintain in good condition your diving equipment. The following may guide you through. These are not absolute measures to take. The final decision is yours.
Basic maintenance: rince with clean soft water
The 1st rule is to always rince your equipment with soft water particularly if you have done a dive in salty, dirty or polluted waters.
Rince with large amount of water your regulator and be sure to remove any trace of dirt. You might be surprised to know that even nothing seems to appear, there is always dirt accumulation (dirt, leaves, sand, etc).
Basic maintenance: avoid unnecessary sun exposure
The 2nd rule in the case of neoprene, plastic and rubber tubes is to avoid unnecessary sun exposure. Do you need to be convince? The sun action discolor and change material properties. Put your gear equipment away of sun exposure when not needed in order to increase its life duration.
Basic maintenance: avoid neoprene crushing
The 3rd rule is not crush your neoprene equipment when you don’t need it for a long period of time. Avoid leaving you wet suit folded at the bottom of you dive bag under the weight of all of your gears. This could crush the neoprene of your wet suit and modify on quasi permanent base its properties like its buoyancy and thermal isolation.
For example, do not suspend your wet suit on thin metallic supports. Use large wood or plastic supports. The neoprene for example at the shoulder region will not be crushed by the weight of the wet suit. Put it in a wardrobe over large supports and covert it with large plastic bags (large garbage bags will do the job).
Basic maintenance: avoid unproper folding
The 4rd rule is not to fold your equipment when you don’t need it over long period fo time. Avoid maintaining the tubing of your regulator for example in tigh loops and folded in an improper manner. This may strech the rubber tubing and create rubber fatigue over the time which may create unwanted leaks underwater.
Basic maintenance: avoid unnecessary elongation
The 5th rule is to avoid to suspend any piece of equipment for long period of time. For example, avoid to put your wet suit over long period of time. This could weaken the stiches or glued joints. Avoid at any price to suspend a dry suit on supports (even the best you could find). They have been not conceived for such a treatment. Avoid to suspend any rubber tubing which can be elongated over time, this could create rubber fatigue.
Cleaning: use a soft soap
Some pieces of equipment may become dirty like the wet suit when you touch or pass near the bottom of a lake, you may use a soft brush with a soft soap to remove the dirt (ask your dive shop or your gear equipment manufacturer).
Cleaning: wet suit boots
This piece of equipment needs a particular maintenance namely due to the odors. You may of course clean them with a soft soap. But the interior will need a soap which kills the germs like for example Febreeze (there are many more; be sure not to be allergic and not use a product which could dammage the neoprene). Let it dry outside.
Buoyancy compensator (B.C.)
You must clean with soft water (if necessary use a soft brush) your buoyancy compensator. Replace the straps to their initial position. Remove any trace of dirt. Empty any water contained inside. Retighen any seal (specially those looking like bottle seal). Ask to your dive shop.
Sometimes regularor or snorkel mouth pieces need to be desinfected, a dilution of javel water can be used for soaking the parts (ask your dive shop if your equipment cannot be damaged by javel water). It is important to do it, read the following (French article) : La décontaminaton du matériel de plongée est-elle une nécessité?
Seals need a fine coat of lubricant. You may find some at your dive shop.
Appropriate kind of wax has to be applied on the dry suit zipper, on average after each 2 dives. Ask to your dive shop.
After a number of dives, a lubricant has to be applied on the wrists and neck seals in order to extend their life and maintain their flexibilities. You will find that at your dive shop.
Apply a talc powder or a lubricant on the interior part of the wrists and neck seals of your dry suit just before diving. You will have less difficulty to wear it.
After each dive, it is mostly preferrable to release the straps to their initial position. First, they are much easier to insert at your next dive. And the straps are not folded at the same place all the time, this increase the life duration of the straps.
Recharge your underwater lamp before each dive according to the manufacturer specifications. You may make a charge test of your battery (the test can be found on the web site of the manufacturer: you may ask to your reseller a copy of it, it is quite long and you will need a multimeter).
Seal lubrification is needed at some time.
Analogic depth gauge
Replace the depth indicator to zero after each dive (after you noted the depth).
Avoid absolutely to put your compass near a large metallic piece or an electric source that could have bad effects on the needle.
At the end of your dive season, it is important to leave some air pressure but not at high pressure and surely not to empty them completely. It is important to leave your tank in the up position. If there is some oxydation (rust for steel cylinder), it will attack a thicker part. You may leave them in place where there is not so much temperature fluctuation in order to increase the life expectency of your air tanks. Please ask your dive shop, because it varies according to brand name and metal construction (aluminum or steel)
On a year basis, inspection of your air tanks has to be done. A visual inspection is needed to check for cracks or metal fatigue. It is also a good time to ask if presence or oil depot was noticeable. Larger the quantity of oil, poorer the quality of air. This is a good sign of how well the air compressor is maintained at the location you make air filling of your tanks. In any doubts, ask questions to your dive shop. And go to another dive shop if the answers do not satisfy you...after all your lungs do the cleaning job otherwise...
The 5th year, an hydrostatic test has to be done in order to check if your air tanks can still support the manufacturer prescribed pressure.
Be sure that the inspection is done by personnel who received proper training and certified by an official agency.
On a year basis, an inspection of your regulator has to be done in order to detect any signs of seal fatigue, check the adjustments and replace any defective parts. It is quite important to do it: your life depends of it! This has to done by trained personnel qualified to the manufacturer of your regulator
On a year basis, an inspection has to be done in order to detect any sign of seal fatigue, check the adjustments, lubricate the mobile parts and replace any defective parts. Ask to your dive shop.
Check for cuts of the neoprene, your dive shop can make repairs in most cases (except...).
Check for cuts of the neoprene...
Check for cuts, an accredited dive shop can make repairs in most cases (otherwise the suit has to be repaired by the manufacturer). Neck and wrists seals can be replaced also (otherwise at the manufacturer)