I personally think that you should treat the lines again based on how much movement you have and what you are looking to achieve from the treatment.
Some patients are happy to leave the treatment for longer than 3 months. This will allow some lines to form again but will allow a bit more movement. Other patients don’t want any movement at all and come religiously when movement starts to appear again.
So – treat it on how the lines look rather than the time frame as it can vary quite a lot between patients.