When the arrow are all red, i think that's the best time to stop trading. Then you can continue when the price all in green. Absolutely trading is risky, i think you better do a long term investment.
Yes trading is risks so best time to exit trading when you have profit. We can do sell some of our coins and hold for long term. Best to do is to be wise of your investment not all investing in single coin only so spread your investment then take profit to exit for a while.