I love kits and 'containerize' everything. This lets me quickly pack heavy when needed or light when called for without missing anything. If I'm going for a hike or a ride on my motorcycle, I include my gear repair kit and I know I'll be covered in case my backpack strap breaks or I blow a jacket zipper.

I can manage the contents of the kits seperately and sometimes I build a checklist for each one so I can make sure they're stocked. A little planning and there's only overlap where I want there to be overlap (like the extra bandages and duct tape I carry in my pocket kit for example).

My fully loaded BOB (a water resistant german military surplus rucksack) is then neatly organized in small pouches (I use everything from pencil cases to waterproof Pelican cases) that are labeled and/or color coded so that I can get at what I need quickly. Be it first aid, gear repair, food/water preperation, fire starting, food gathering, etc.

I also use these kits when I'm camping or hiking. I don't like 'saving' them for an emergency since a lot of the stuff that's packed expires (like meds, or water purification tablets). One kit contains a Moleskine and a Fisher Space Pen which I use to make notes...often when something is missing from a kit that I hadn't thought of or when something doesn't work and needs to be re-kitted/re-packed so I'll remember when I get home and can improve the kits over time.

I just pack the kits I need into one of the larger pouches in my hiking pack...it adds a bit of extra weight but it's worth it to be organized. If packing light I'll use a hikers fanny pack or a Scott e-Vest which can then contain everything I need without mess or fuss. The other nice thing is that if I can go from scratch to a fully packed BOB in just minutes regardless of which bag I use...though I typically store it packed and ready to go.