The green is wet or it is windy and you are 80 yards or less from the pin.
The green is wet or it is windy and you need to get the ball over the fringe. You are poor at chipping and are a short distance from the green.
You need to improve your hand rotation or squaring the clubface at impact.
You hit your woods better than your irons and want to improve on your iron shots. You may even notice a divot that begins before contact with the ball instead of after the ball as it should be when using your irons.
You need to learn or a refresher course with the putting fundamentals.
You need to learn how far you should bring your hands back while pitching.
You have difficulty putting due to overanalyzing or trying too hard to make the perfect putt.
Your ball has landed on a hill and you need to learn how to play it.
You need to draw the ball in order for it to land on the fairway. When you draw the ball, it should start to fly towards the right of the target line then curves left.
You are having difficulty reading the break in the green.