For a travelling kit I take a bit of a different approach, and the approach changes depending on where I'm going.
A liveaboard trip is different from a local dayboat or Bonaire kit. I'll take a lot more stuff for a week-or-more LOB trip vs a "my risk is missing 2 dives" trip on Bon or on a dayboat.
I start with a couple of fundamentals:
1. What size are the nuts (and there may be several sizes) on my equipment? this usually results in 3 open-end wrenches.
2. What size hex wrenches do I need? Usually these are for the plugs on regs, but may be used on reg internals if I'm feeling frisky. Usually 2 hex keys.
3. Any brand-specific tools (looking at you Scubapro and that stoopid non-standard spline-nut) that may be required.
Abandon the adjustable wrenches and multi-tools - these things are the spawn of the devil useful for rounding nuts or scratching chrome. Some people love them, and different strokes for different folks. I Get the wrenches that <I> need in the form of "bicycle wrenches" - that is, thin wrenches that will fit the nuts where hoses connect to 2nd stages or to first stage. The come in bundles, and Amazon is your friend. This will result in a small/light bit of kit. Also, buy $tainle$$ if that is what you want. It is stain-less, not stain-free. I buy cheap wrenches, rinse them well, WD40/wipe clean occasionally and they last a long time. But that is just a matter of my preference.
If you find any screw heads on your equipment that you might need to remove get screwdrivers specific to those screws - think bands on wristmount gauges, the back of computers for battery changes and the like.
I include small scissors. Useful for cutting line/bungee/webbing.
The spare parts list above is a pretty good one, especially the pressure gauge spool and replacement inflator assembly.
The o-ring picks in the link are good because they are soft, bad because they are soft. I use dental picks - free from a dentist friend, bad because they are hard, good because...
I buy my O-rings by size and usage, not in a kit. Then I bundle them up in the numbers/sizes that I have found I need for travel. DGX is my source. They have a handy document of o-ring sizes and uses. They're probably not the cheapest source, but they are a fantastic resource I like dealing with them.
As you might have noticed, this is a kit FOR ME. It fits my gear, not everyone else's. I guess I'm a selfish bastid, but I'm trying to build a Save-MY-Dive kit, not a Save-Anybodys-Dive kit so I pack stuff that fits me. It's a small light bundle that works FOR ME (and incidentally has worked for others-in-need on the boat from time to time).
All above is my opinion based on my desire to avoid acting as a pack mule - and to have the stuff that meshes with my equipment.
To me, my kit is very personal. I wouldn't want my lovely bride to try and buy/outfit one for me. But a shopping spree at DGX, Scubatools, etc. - yea boy, I'd go for that! Buy him a bag to contain the goodies and put a gift certificate from your preferred vendor(s) in it for him.
I also don’t want to buy a $30 kit, and wind up with flimsy tools that don’t work either. Suggestions? Any input greatly appreciated!
