The profit taking between traders and investors is different, but in principle it must have the price target. Before we buy/sell in the market, we must have a careful plan so that we can stay in the market for a long time.
The market is very dynamic. No one in this world can accurately predict the direction of the market. If you are absolutely sure of the prospects of the portfolio you hold, then I don’t recommend selling everything. If you are not sure, it is best to take all profits and mix in a new portfolio that is still promising. The market will always go through a "bearish-sideways-bullish" cycle, so we need to learn to take profit/stop loss.
Learning how to trade is one thing and taking profits is another thing which can be imperfect at times because there is not always a best time to take profits. The market moves in a big zag manner which makes the market perfectly unpredictable with no time to determine what will happen next in the market.
Taking profits have to be a target base thing that is focus executed to take out already made profits that had been made in the market. Where taking profits, there are tools that traders uses to analyze the best time to take profits with the use of technical analysis.
It's better to take your profits when the market is in profit at any time than to leave the market with loses which is unwise. Greed had being an obstacle to traders when it comes to taking profits in the market which had affected many traders to end up there trades with loses.