I have kept an open position for about a month and have never faced any problems unless my trades are charged swap fee. But is there a time limit that we can keep our trade in, let's say can I make my trade open for several years, I think there is no such limitations. I also have some trades opened three months ago. And one of my friends has held his position for more than two years. So I think there is no such limitations. But if you get a negative swap for trading, you will lose a lot of time