Well if u research n bought into long term investment compan...

Well if u research n bought into long term investment company buying high way out will be dollars cost averaging if the price drop. If u are trading buying high best to cut if price dropped 20% to preserve the capital n deploy it to other stocks. For momentum trading high gets higher but once trend reverse better follow n get out. Well easy said than done as we human are all emotional animals n hard to admit n realize loss....