Each of my vehicles has a 24 hour kit and a 72 hour get home bag. The 24hr kit is a very small zipper bag that was actually inspired by a fairly good emergency kit that came with my Subaru.

Folding shovel
Mylar space blankets
Glow sticks
Candles
Matches
Flashlight
Lighter
Basic 1st aid kit
Pocket ponchos
Lollie pops to calm a potentially cranky kiddo
Diapers
Sealed bags of "emergency" water
And a few other things you might need if you got stranded on the side of the road overnight or in a snowstorm and can fully expect someone will be coming to pick you up.

The 72 hr get home bag is for a bad situation. It's a small backpack filled with additional items such as water treatment, food, rope, knive, more water, ammo, advanced 1st aid, batteries, head lamp, pocket solid fuel stove/fuel, small pot, more substantial sleeping bag style space blankets, compass, Colorado map, socks, diapers, travel sized game for the kiddo and some other things.

Also things in my car always but not in the kits are wool blankets, outwear and a flat of bottled water.

I don't have true BOBs at home. I have plastic totes filled with the items I think I would want to load in the truck if I only had a few minutes to G.O.O.D. Leaving on foot is my very last resort.