Today I covered a position in the world's simplest ticker symbol, ABC. I had shorted this stock when it broke its ascending trendline (circled). It had fallen about 14%, and as it approached its former breakout level (the horizontal line), I covered in the tinted green zone. Because this chart only covers a portion of the entire price history, it isn't clear to you that the horizontal line is a big breakout, but trust me on this one.
I offer this as an example of a rational time to "take profits". Yes, this stock could go lower, but this seemed like a logical time to reduce risk and take the 14% given to me.