Analyze the type of coin you are holding. See if there is really a good future ahead of it or it is already an abandoned project with no real and meaningful activities done by the team behind. Sometimes a coin or token may surprised us but generally speaking things are hinging on the kind of vision and how good is the team behind that vision. This is not a guaranteed way though as some coin can have a good team but still the market is not responding well. So it is then your call whether to let it go or to hold it indefinitely.