Well it depends on what is your plan with your trade. If you invest it for long term then I think you shouldnt be worrying it. If day trader then apparently within the. I usually take profit if it hits 5-7%. This will be a more realistic target. Search for a volatile coin and have a good volume so that you can get out easily. For midterm I think 20-30% is sufficient enough but if I am  anticipating news that may give a big impact to the coin then I just set a stop loss then if it gets higher then I just adjust my stop loss. As they always say have a trading plan before entering any trade.