What is your chance to buy cryptocurrency at the most basic price? and how much is your chance to sell crypto currency at the top of the price? The reality is that buying and selling cryptocurrency will not be possible with perfect timings.
Define a strategy. How many times did you sell and buy cryptocurrency in one week? Some people want to be daily traders, but many people have proven that holding for the long term is more fruitful. A strategy I always tell friends who are new to cryptocurrency is "buy and hold". The longer you plan to hold a cryptocurrency, the more risk you face. Unless there is an unfortunate indicator of what is going on behind a cryptocurrency, then you must make a decision to cut loss (sell it).