Why it's really hard if you want to sell or carry on a long-term basis. So long so uncertainty occurs and the price fluctuates from time to time, you will benefit from it. Don't presume the market will always show green colours because it can not happen. The most important thing about this is just that you know the right time to buy and sell money. The price of Altcoins was tied to the price of Bitcoin and it's almost the same movement.