The good thing about Paida Lajin is that you can practice it at any time of the day: morning, afternoon, or evening. You can easily make a habit of this healthy technique, especially when it comes to stretching.
Just like medicine, different individuals will respond differently to paida lajin. Moreover, the therapist does not specify the amount of time you should spend practicing this technique. The duration, therefore, does not matter since there is no way of knowing when sha will appear or disappear. However, children, elderly individuals, the sick, and other people with frail health should follow the recommended sequence. You can search for paida lajin videos on workshops held by Mr. Xiao to get a clue of how they are done or visit the Pailala Institute. He advises his clients to determine the practicing duration depending on the case they are addressing; is it a health, sub-health, or other cases?
If you are practicing paida lajin for health purposes, you should slap your head to foot for about 15-20 minutes each time. The shoulders, armpits, knees, and the elbows should be slapped for 5 minutes each and at least twice every day.
If you are doing it for sub-health purposes, all the discussed parts should be slapped and patted for longer time. This means you could slap the parts for about 5 to 30 minutes depending on the results you desire.
If you have a serious ailment, then you might consider extending the Paida Lajin practice time to over one hour.