As we're told over and over again, the secret to successful investing is diversification. If you want it in plain English, don't put all your eggs in one basket.
Now it does depend upon the size of your investment portfolio: it might well be that you'll be best served by some cash and an index linked fund. But once you get over a certain size you'll want to be more proactive in how you organize your diversification.
You'll want to make sure that you have a spread of asset classes: most importantly, that you have things which react differently to outside shocks like inflation. Bonds, for example, fall in value when inflation rises, just as they rise when it falls.
To protect against this you want to have some money in assets which move against this cycle. Gold bars are one such: Traditionally, when inflation or uncertainty rise, so does the gold price.
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