If you have to hold down the switch for your garage door to go down, there is definitely something wrong. A misaligned safety sensor is most likely the cause of the issue. There is a small light on each sensor. If nothing is in between them, they should light up. If you do not see any light at all, it is time to replace them because sensors go bad over time too. You can also check if there is direct sunlight towards the sensors. This can also make them misbehave.
The problem can also be caused by a bent track or broken wheel. You can determine if it is indeed that problem by checking for resistance. With the door closed, pull the red handle to open and close the door. Ideally, the movement must be fluid. If there are tough spots along the way, you can call your local garage door repair company to fix the bent track or broken wheel.
