To speak to the volume of my stuff, I have a 4x4 truck throwing this gear in the bed of the truck gives me traction and the gear is functional. So rather than driving around with sandbags in the back of the truck for traction (it is rear wheel drive when the 4x4 isn't engaged) I have gear that I can use.
Oh, if I had a 4x4 I would stuff it with stuff... absolutely.
Having a more modest family car (actually, quite roomy) I am very much against filling the cargo space or the passenger compartment with all kinds of stuff. We no longer haul strollers around, which gives a bit more room for emergency equipment, but I still hate having stuff perpetually rolling around back there. The only thing back there is actually the first aid kit (velcro'ed to the side panel) and the emergency triangle, both designed to live there by the manufacturer (and no way to fit them anywhere else, or I would move them too...)
I make great use of the spare wheel drum, which holds a minimalistic "emergency-only" tiny wheel in a normal size wheel drum. This leaves quite a bit for the most basic equipments, including
- Tools
- Jumper cables
- Towing rope
- Gloves
- Poncho and plastic rain suit (single use only)
- 1 litre of sand
- the NATO folding tri-shovel equivalent
- chains
In winter, I add an avalanche shovel (plastic) and some wheel mats (3' long plastic thingy to put under the wheels when stuck in deep snow, untested but probably far better than the floor mats, which I never have been able to make work). I also add a few extra window scrapers and snow brushes (the kids fight over them whenever the car needs scraping or brushing, so I just toss in a few extra). Oh, and I put on really good winter tires.
Glove compartment holds a lighter, flashlight and Mora knife. Side panels hold reflective vests (required by law) and working gloves.
Frankly, we either just drive around locally, in most cases we could just walk home if stuck. And when we drive further away we usually do it for a purpose involving either a day trip or an overnight trip. In both cases we're fairly well equipped.
I am in the process of rethinking this strategy and put together a bigger car cit, along the lines of some food, blankets and such. We'll se how it works out.