As with most services, tipping is customarily based on the cost of service and how pleased you are with your session. Excellent service, above and beyond expectations: 20%; Good service, all expectations were met: 15-18%; Satisfactory service: 10%; Poor service: do not tip any service provider anywhere if they failed to meet your expectations. Communicate that you did not receive the service you expected so that appropriate adjustments may be made. A note: If you do not pay for the service you receive, if it is paid for by your employer or a vendor with whom you do business or if it is a gift, it is customary for tipping to be included in the price your benefactor paid. If you wish to show your personal appreciation please feel free, but know that it is not necessary. You may want to inquire before your session if the tip has already been taken care of.