I am of mixed opinions about PMs. Gold especially has been an historic hedge against inflation, and has never been worth nothing, as its proponents like to point out. Those holding PMs will watch their stash increase in value in dollars, euros, loonies, whatever. Eventually, fiat currency will tank, and people will only accept commodities of hard value.
There are, however, some things to consider. First of all, assuming you're going to cash in your PMs, you're going to cash them in for what, exactly? A larger amount of some failed fiat currency which will eventually only be good for wiping your hind quarters?
OK, you're going to hold your gold and barter it for... well, for what? Joe Prepper with his stash of food might or might not accept your gold... he already has what he needs for survival, why should he give this up for a shiny bit of metal that he can't eat. If famine becomes widespread, you won't have anything to trade your gold for, anyway.
As I've said before, I'm a hardcore Christian, and I firmly believe we're headed toward the end, complete with the cashless society that will accompany the guy they call the Beast. Gold isn't going to do a whole lot of good in that scenario, either.
Last one. The .gov confiscated gold in the last depression. Who's to say they won't try that, as long as they'll be confiscating things anyway...?
Food. It's worth something now, and is only likely to go up in price.
Water. My fat self can survive without food for quite a while, but I'm dead in 3 days without good ol' Dihydrogen Monoxide.
If I have anything left after I get those 3 things in order, I might get some silver, but not until then.