The longer you are alive, the higher the odds are that you will make it in the long haul.
I am working on the premise that surviving several weeks will jack up my long term odds a huge amount. But I am shooting for preparations of 3-6 months on as many fronts as is realistically practical.
Food and medicine stores for the longer haul. Water for prep for long term is very tough. Gotta be realistic about that, unless I win the lottery.
Bugging out? Multiple storage areas and destinations? These are impractical for most of us. So we store what we can and plan to protect it as best we can.
I am old enough that the realistic attitude for me is to stand my ground. Either I hold my ground or I make those that take it pay a heavy price. I think I am sufficiently equipped to do one or the other.
One final thought. The really scary thing is that in the event of a SHTF, it is just as likely that the forces of our government will as much a threat to our individual survival as our fellow citizens.
It's not that hard... Maybe it's because I grew up in a family that builds water and sewage treatment plants for over 100 years, but we have local surface water, a water table that in the rainy season comes up to 2 feet, and we get about 30" a year here.
And it's not hard to make it safe.
Remove the stuff from it. Whatever it takes. Filter through gravel and sand to remove big chunks, drip it through charcoal to remove the bad flavors, add chlorine or idodine or boil it to kill the bitty nasties that are left.
Add air to it to make it palatable.
/johnny