The difficult thing is to identify those movement and take the risk to place orders. You may see a downtrend but even when you buy it might drop even more. There is also possibility that while the uptrend is ongoing, you may sell but the price keeps on rising. The key point which I am trying to highlight is that one should not become greedy during such movements. Whatever price you buy at or sell at be happy with that. Otherwise you will panic buy or panic sell.

If you have some important news that may have a good impact on the market and you already have some altcoins in holdings that you want to cash out of then its the reason. If you dont have any other coin then why bother.