'Discerning' passive investor = Buy at troughs (or when gold spot price reaches statistical moving average line), wait for long-term significant appreciation

'Active' investor = Buy at troughs (or when gold spot price reaches statistical moving average line), wait for medium-term significant appreciation (normally 6 to 12 months), sell at peaks, buy again at new troughs (or when gold spot price reaches statistical new moving average line),

Gold bug = Buy at any cost [but don't be in debt], mostly physical gold, keep under bed 

(Selling at peaks should be done if you'd like to use that gold for monetary use anyway)

This is how I define gold investors anyway (the other analytical definitions too are useful). Maybe a combination of these strategies are useful.