You need to acquire it all, 1 piece at a time. No rush, we don't have a date for collapse! I just like to be ready when things go wrong.
We have been stranded with the power out for 5 days to 2 weeks, floods, drought, snow, winds that take out our 200' tall trees, etc. When all the neighbors are scrambling, it sure is nice to be calm and prepared!
We are digging a root cellar this year and installing a commercial greenhouse, all for personal use. It is not a race, it is a personal accomplishment to be prepared. I look at it this way... I will have to eat for the rest of my life, and I am proud and happy to be self-reliant. No food tastes better than the food you generate yourself! And think of all the petro you save not running to the store every time you want something to eat!