Specifically, in certain SHTF scenarios, how long before it would be safe to venture from your location and rejoin 'society'. Started thinking about it when I was wondering about how much supplies we would need for various 'doomsday' scenarios. Now in a nuclear catasrophe scenario(whether a power plant is comprised by man or nature, or WMDs, doesn't really matter, the outcome is the same), I doubt it'd be safe to go out during the rest of my lifetime. In a pandemic scenario, I figure(depending on the incubation period of course), that in 3-6months(based on previous ones and the global everyday travel that we didn't have then), the majority of it would be over. EMP issue, I've heard estimates that it would take the US 10years to rebuild the power grid(which is kinda funny, because by then I think those with a brain will either already have their own power source, or be used to doing without). Other things like famine, volcanic eruptions, another civil/revolutionary war, etc., I view those as having so many multiple factors affecting the severity and affected locales to give any sort of reliable estimate. I am not including other natural occurences because A: I hate the words 'natural disaster' for stuff like this, especially when it's used by people who live in areas commonly hit with the same type, and get all bent out of shape every time it happens. To me a natural disaster is when people poison the planet, and B: earthquakes in L.A., tornados in the Midwest, hurricanes in the Southeast, they are not uncommon and tend to be localized with short-term damage(well it would be short-term if government wasn't such a you-know-what...are there still places in New Orleans that never got cleaned up after Katrina?).