Yes! you do not need to have any scalp conditions to benefit from a Japanese head spa treatment. Read more about the benefits here.
The time it takes for a Japanese head spa treatment will depend on the package you have chosen. Usually it takes around 1 hour for a relaxation treatment and 1.5 - 2 hours when treating specific scalp conditions.
Treatable conditions can be found here. If you have a serious medical condition, you should seek the approval from your doctor before having a Japanese head spa treatment.
Sure, you can find out all about it here.