If you are a swing trader, your timeline for holding a stock can be very short. For the swing trader, the catalyst is the determining factor. That is, you believe a stock will move for a particular reason. The time to sell is when the thing has happened, and the market has responded to it. Many things move stock prices, and you will have to make this part of your financial education if you want to swing trade. The vast majority of people that try it lose money swing trading. They make bets on whims, and they suffer losses. Swing trading can make you money, but you have to be disciplined, trade on rules, and have excellent theses as to why a stock will go up or down. The only way to do this is to spend a LOT of time watching the markets and learning what catalysts move what stocks how much. Unless you can devote a lot of time to developing a winning strategy, stay away from frequent trading and focus your efforts on long-term investing.