President Trump threatens to “totally destroy North Korea.” Another hurricane lashes out. A second monster earthquake jolts Mexico. Terrorists strike in London. And that’s just this past week or so.Yes, the world is clearly coming to an end. But is there anything you can do to prepare? That is not a philosophical question, or a theological one. And if it is a question that seems to beg any explication, you may stop reading now.But if you are among the swelling class of weekend paranoiacs of affluent means who are starting to mull fantasies of urban escape following the endless headlines about disasters, both natural and manufactured, you may be starting to see a different image in your mind when think “survivalist.” You may no longer see the wild-eyed cave dweller in camouflage fatigues, hoarding canned goods. You may even see one in the mirror. In a world where the bombproof bunker has replaced the Tesla as the hot status symbol for young Silicon Valley plutocrats, everyone, it seems, is a “prepper,” even if the “prep” in question just means he is stashing a well-stocked “bug-out bag” alongside his Louis Vuitton luggage in a Range Rover pointed toward Litchfield County, Conn. Here is a checklist for the neo-survivalist preparing for the apocalypse.Go for the Silver Two years ago, Greece was forced to shutter banks and limit A.T.M. withdrawals to 60 euros a day during a debt crisis that threatened to shatter Europe’s currency union. In the United States, prominent authors like James Rickards, a hedge fund veteran, and David Stockman, once the budget director for the Reagan administration, insist that an even bigger crisis will soon tank Wall Street and torpedo the dollar. No wonder so many preppers, some of them wearing pinstriped suits, consider gold and silver to be a crucial hedge against a crisis. While Bitcoin and other cryptocurrencies make news, many preppers are quietly packing their bug-out bags with rolls of pre-1965 American dimes, quarters or half-dollars, which are 90 percent silver and available from coin dealers and precious-metals websites (silver is currently about $17 an ounce). “My preferred form of precious metal post-financial collapse, that is, besides high-speed lead,” wrote one prepper on SurvivalistBoards.com.Unlike gold, which is hovering around $1,300 an ounce, these old silver coins come in small enough denominations to barter for a loaf of bread or a socket wrench in an economic “Mad Max” scenario. Even so, some survivalists remain silver skeptics. “For $100, let’s say you get five silver coins,” said an urban preparedness expert who goes by the nom de guerre Selco. “Why not buy 100 cans of soup?”