I think that it is very important to have some of your portfolio in a tangible asset... and gold is definitely a nice choice.
I would suggest having 20% in precious metals, 60% in silver and 40% in gold. Precious metals are like financial insurance, similar to buying insurance, but with one exception: you have the asset, not a policy which is subject to a company's management or mismanagement.
No human being on this planet knows that answer. The best you can do is an educated guess. Traditionally when hard times appear everyone runs to GOLD for protection but that doesn’t mean the past equals the future. Mere humans will never know the future of any investment.
If you invest in the stock market you are likely to lose your money. But investing in gold is usually safer.
Invest in bullion, the gold always rises or stays, and in case of crack (that goes down), you just have to wait for it to go up. On the contrary, if the stock market is going to sink, you get nothing at all ;)
Central banks in Britain, America and Europe are expected to raise interest rates in 2018. This and the rise of the dollar has caused the fall in the price of gold. Investors are buying gold at low prices as a refuge asset. So 2018 could be the time to buy more of the precious metal. And, even in the worst scenario, gold will always have value.