Bitcoin is the future currency,we can buy and sell any time.because this is very good investment.nowadays bitcoin is very popular,buying and selling bitcoin is the good business.today also we can buy and sell,but once have to check the price of the bitcoins.if the selling and buying gives money we can buy/sell.that is your wish. 
Thats a comprehensive and simple explanation given in a nice way. I second your piece of advice. Exactly, there is no time limit of buying and selling bitcoins; you can do so according to your needs. But if great profit is desired and you want to make money within short time, its wise to buy bitcoins when prices are continuously dumping and buy coins again when they are facing a tremendous rise. This simple strategy will help you a lot in trading with bitcoins.