For longer term trades, is there a good rule of thumb as to how long to keep a long position when it's just moving sideways? I want to make trades that gain 3-5% and then exit. But sometimes, I will take a long position and the stock decides to go sideways. If after a week and it doesn't move much, should I get out of the trade and look for something else? Or should I stay with it? Does the probability of the stock going down increase the longer I keep it? Or does it stay at 50/50?

For the long time, experienced traders, do you have any guidelines or advice? Thanks in advance!