I guess it depends on if you have to be completely self-reliant or not. For me, my BOBs contain supplies and tools enough to get me out of harm's way, which I figure could take a day or two or maybe three. After that, the consumables are pretty much gone, leaving me with a robust survival kit of tools and implements that I can use for an extended period. Security, water purification/filtration, shelter and clothing, fire, food, first aid, signaling and orienteering are the longer term requisites that make up the durable goods in my pack.

If it is complete self reliance, then I have enough to keep me going for a good three days. That is about all I want to carry with me anyways.