Once each month you should be checking to see if your various stocks are advancing as planned. Forget all those pretty research reports your broker sent you. Burn them. Now you must not care anything about that company. What you care about now is your money. As long as the stock price is advancing you may continue your love affair, but when it starts down it is time for a divorce. Time to leave before the damage gets worse.
This is where emotion becomes expensive. If you just bought it your ties are strong and you know if you sell you will have a loss. Never fall for that old broker’s adage that you don’t have a loss until you sell. Anyone who believes that will be eating cat food at retirement.