The reason is because all too often the price can drop and you will end up giving up that profit. Instead, as soon as I’ve reached my first profit target (if I’m risking $100, then as soon as I’m up $100), I’ll sell 1/2 my position and set my stop at breakeven. This method of scaling out ensures small profits on all trades that move in your favor, giving you a better percentage of success.
Many times, neither a bullish nor a bearish trend is present, but the security is moving in a somewhat predictable pattern between parallel resistance and support areas. When the market moves up and then pulls back, the highest point reached before it pulls back is the resistance. As the market continues up again, the lowest point reached before it climbs back is the support. There are swing trading opportunities in this case too, with the trader taking a long position near the support area and taking a short position near the resistance area.
Scalping is a trading strategy geared towards profiting from minor price changes in a stock's price. Traders who implement this strategy place anywhere from 10 to a few hundred trades in a single day with the belief that small moves in stock price are easier to catch than large ones; traders who implement this strategy are known as scalpers. Many small profits can easily compound into large gains, if a strict exit strategy is used to prevent large losses.