As long as there has been no official country use bitcoin then I dare to keep a long time, this is because the price could drop by up to 30% in 3 days only and it is often the case, I'll sell when I think already get the profit.
What does that have to do with anything? Sure, it's a very volatile currency, but just look at the long term trend, if you hold long enough, the price will just bounce back again.
Unless something really serious happens.