Insulation tape, although easy to find in electric hardware, does not tend to stay on well when used in small squares. My main ID color tapes are fabric based and stay well on smooth surfaces when cut into small squares and rectangles of 1/2 to 1" size. On canvas bag handles it does not hold as well, unless it can be wrapped completely around the strap with both ends of the tape overlapping. This way, it sticks to itself for staying in place and becomes a loop/ring around what it is attached to. I also do this to light stands and other round things, sometimes cutting the tape into narrower strips in a length that will completely encircle the item. Reflectors and soft boxes usually get just a square. My ID color is bright, so this helps when packing up in dimly lit areas after a shoot. Black is a great non-reflector and why most photo gear is that color, but it's also a major reason why photo gear gets left behind in the haste of packing up. Permanent metal markers are great, but I chose brightly colored Duck Tape to help me easily see my gear in dimly lit locations. I'm less worried about theft and more worried about accidental loss, so brightly colored marking was my choice. I have luggage tags with my business cards laminated in them on each camera bag for personal property identification. The color squares, etc. are to keep me from leaving things behind and to keep me better organized. It's a near death blow to arrive at and set up for a shoot, only to discover that you have left a critical bag behind in the studio. I'm also a "bag counter". I count how many bags go into my car when going on a photo shoot. I count them again when unloading, and count them again just before setting up, to assure that my help hasn't left anything behind in the elevator, etc. I then repeat the process in reverse to assure that everything arrives back in my studio. My color coding methods are an attempt to prevent accidental loss, if at all possible and not so much a theft control.
Charley