The increased inflation rate in the 1960s, the US monetary devaluation, the continued concern over a possible nuclear exchange between the US and the Soviet Union, and perceived increasing vulnerability of urban centers to supply shortages and other systems failures caused a number of primarily conservative and libertarian thinkers to promote individual preparations. Harry Browne began offering seminars on how to survive a monetary collapse in 1967, with Don Stephens (an architect) providing input on how to build and equip a remote survival retreat. He gave a copy of his original Retreater's Bibliography to each seminar participant.
While survivalists accept the long-term viability of Western civilization, they learn principles and techniques needed for surviving life-threatening situations that can occur at any time and place. They prepare for such calamities that could result in physical harm or requiring immediate attention or defense from threats. These disasters could be biotic or abiotic. Survivalists combat disasters by attempting to prevent and mitigate damage caused by these factors.
To me, the best option is to store emergency food. How much? If you have none, store enough for a few days. If you have enough for a few days, get enough for a week. How much you store depends on what time frame you think you're at risk for having to be completely independent. The early settlers of the southwest liked to store enough food for a whole year and still do to this day!