IMO it goes like this:

I figure three to ten days where I'm entirely isolated and totally dependent on what I have on hand to provide water, food, shelter, medical treatment, transportation and security.

Another ten to thirty days where there are shortages, limitations and interruptions in normal resources availability.

Six months to a year of minor disruptions and adjustments. You never really get back to the way things were. Over time people usually adjust and accommodate the new situation and after a time it becomes the new normal.