Here's a basic rule if you plan on holding your coins in order to become incredibly wealthy.
Don't ever "cash out". That is, convert the coins into fiat currency in order to make them more liquid.
Wait until you're able to spend them on everything, from insurance, to property, to groceries and etc. This is when their value will be realized by the world.
Indeed. Bitcoin will be mainstream when the old ladies on the street start talking about it. Then, there will be no real reason to cash out.