FWIW, I have stashed a few old duffle bags and old kids backpacks as car BOBs. An old duffel holds the stuff, but backpacks are almost empty and would be carried by kids ( if they are with me) or if I may need extra carrying capacity for whatever I can find on my way in stores, gas stations .. etc.

I dont think I would spend much money for bags and packs that would just be sitting there. If I use them and they tear, I will use the empty packs, or trash bags or whatever. The possibility of The world ending and finding myself with my life depending on a bag or pack is just too far for my mental setup.