DIVE LIGHTS:
Tip 1:  Avoid dive lights that require an extension cord
Tip 2:  Never buy a dive light that advises: "For day use only"
Tip 3:  Be suspicious of a dive light that suggests you ground yourself before using it
Tip 4:  Never buy a dive light that utilizes a wick and lighter fluid
Tip 5:  Never remove the batteries to make the dive light more buoyant

SPEARGUNS:
Tip 1:  Always sight first before pulling trigger.  If the point seems impossibly
            large, or the the grip ridiculously small, try reversing your hold on the speargun
Tip 2:  Never buy a speargun equipped with a silencer
Tip 3:  Never buy replacement tips that guarantee:  "Able to penetrate the the hardest
            corals"
Tip 4:  Remove any fish from the tip before attempting second shot

GAUGES:
Tip 1:  Never use a tire gauge to monitor air consumption
Tip 2:  Never buy a compass marked in degrees Fahrenheit
Tip 3:  Never buy a depth gauge incremented in MSW (miles of seawater)
Tip 4:  Never use a dive table whose no decompression limits are denoted with: ?
Tip 5:  Never buy a dive watch that comes with a drain plug
Tip 6:  Never use a depth gauge as a hammer.   Use a rental tank instead

UNDERWATER  CAMERAS:
Tip 1:  Never change film underwater
Tip 2:  Never change lenses underwater
Tip 3:  Never forget Tips 1 or 2
Tip 4:  If you forget Tip 3, buy camera insurance

Maintenance:   To prevent build-up of corrosive salts, rinse the photographer thoroughly after each dive

DIVE  PROPULSION  VEHICLES (DPVs):
Tip 1:  Buy from a reputable SCUBA store.  Be suspicious
            of  home-made DPVs, especially if the words "Naval Ordinance" or "MARK IV Torpedo"
            are stenciled on the side
Tip 2:  Handholds should never be welded to the propeller
Tip 3:  Be suspicious of any DPV that recommends plutonium as a power source