Continuing from the previous post. Comments generated some good discussion, responses started getting long so I broken them out here.
Contractor-style "Go Bags" - maybe a bad example
I used these as an example of a lighter weight, purpose-driven kit, but may have taken the conversation sideways a bit
For some context, an example from Bubba over at DVM of a go bag (he calls it a red zone bug out bag) he carried as a backup: http://www.deathvalleymag.com/2010/03/16/civilian-contractors-red-zone-bug-out-bag-part-1/
A man purse with mags and tactical gear isn't something I'd make an across the board recommendation on, especially for a civvy survivalist. In fact, it's tough to make any kind of across the board recommendations. Why?
A really good quote from the DVM article:
It’s all about defining the threat environment you operate in, the problems you will most likely face, and sorting out the tools that are the best fit for you and your mission, as well as what you can reasonably expect to carry.
The contractor go bag is an example of a solution for the problems those guys were facing in Iraq. They were almost exclusively operating out of vehicles in a quasi-urban environment, and were primarily concerned with attacks from heavily armed insurgents, IEDs or a combination of the two. If the bag needed to be employed, it'd need to be grabbed quickly, and would be used to retreat under fire and either get to safety or survive until help showed up.
Your threat environment, the problems you will most likely face, and the problem solving tools that will work for you will likely be different from a contractor in Iraq circa 2009.
Bug out bag or Ruck
These are two terms that are tossed around a lot in the same discussion--I'll define them in terms of capacity and weight and discuss.
Bug out bag (aka patrol pack, go to hell bag, go bag): A typical bug out bag is going to be around assault/3 day pack size. Or similar to the size you'd take on a long day hike or 3-season overnighter.
Less than 3000 cubic inches and 30-ish pounds or less in weight.
Intended to grab and go in an emergency or support short term operations away from a vehicle or base camp. Keep you alive until you can reach safety, get back to camp or help arrives.
Ruck / rucksack: A larger internal or external frame pack intended for heavy loads.
>3000 cubic inches, 40+ pound loads
I view rucks as more of a special purpose item. These haul the larger quantities of crap you need to set up a comfortable base camp and live longer term in the wilds. These are intentional off-grid operations (e.g., you planned on walking into the woods to spend a week reconning an enemy position) or cold weather ops, where you need a lot of bulky stuff to stay alive.
Due to its size and weight, mobility is hindered while wearing the ruck, more calories are consumed and there's more wear and tear on your body. Thus, a bug out bag is often integrated with the ruck, in case the larger pack needs to be ditched in an emergency or left behind after base camp is established.
Ideally, you would have both a bug out bag and a ruck to work with, or a ruck that can cinched down to a smaller size fairly easily. Options are good. But, they're also costly.
IMO, if you're going to have just one, the bug out bag is the more useful, general purpose of the two.
And, as we've been discussing, you need to consider your environment and the mission at hand--as an example, if you're preparing for the contingency that you might need to walk a hundred miles through the frozen north when it's -40 out, you're going to have a hard time getting away with a smaller, lighter weight pack.
"Civilian" scenarios & loadout
Speaking in terms of situations (and I'm hoping somebody will correct me if I'm wrong), I feel like a civilian loadout is going to be much different from a combat one (aside from the obvious). If you're a soldier and SHTF, then doesn't that mean people are shooting at you, or pursuing you? Bottom line, you are in an actively inhospitable environment. Whereas a civilian SHTF scenario is probably not going to be as actively hostile. A car crash, an earthquake, even (the vastly less likely) event of some sort of terror attack--these are all going to be over quickly. Aftermath, yes, absolutely. That's obviously a danger. But I don't see survival gear as being all that important in a civilian bag unless you're in the boondocks. In an urban setting, E&E isn't as important as being able to render aid to yourself or others in the immediate aftermath of an event. Being mobile (as Theother Ryan pointed out, just walking half a mile would take you out of danger) is the second most important factor.
In thinking this through, there's really kind of a split.
In the more common situations you're talking about, a bug out bag isn't really needed. Earthquake...you're going to just bug in. Car crash...more of a personal SHTF, where you'd want some first aid gear, vehicle extraction tools and a cell phone. Bugging out after a large-ish terror attack (say bio attack or chem weapon)...you pretty much just need distance and a bit of time to let authorities clean up the mess. Cash, a CCW, working cell phone and a hotel room 300 miles away get you through most of this stuff.
But in the above situations, you have the luxury of remaining a regular old civilian.
Then, there are collapse scenarios, where there's little/no rule of law, and you may not have the luxury of remaining a regular old civilian. A prepared person might be pressed into a combat/peace keeper role, find themselves specifically targeted by hostile groups, etc.
In my opinion, this is when the bug out bag starts to become more relevant to your immediate survival, the civilian lines start to blur and the contents take on a more tactical lean.
See the crap going on with ISIS right now for an example...a lot of people who were previously 'civilians' have been forced to bug out from their homes and take up the fight against Islamic extremists. Or areas in Mexico, where citizens are taking up arms to secure their towns and fight back against corrupt law enforcement and drug cartels.
Of course, there's blurring of lines and levels in between the two. A slower slide into collapse or quasi-collapse, where there's sort of a rule of law, but crime is rampant. Dudes who bust out the long guns when looting breaks out. That sort of thing.
As before, do your own threat assessments and considerations, though it always pays to have options that you can scale up/down and adjust as necessary.