Do I need to take all of the training to update for Retail Sales (RS)? October 07, 2021 02:24 Updated YES. If you are purchasing the Re-Certification Course you will be required to complete all training modules as well as the Final Test. Click Here to find out what to expect. Related articles How do I start my test? What is the Re-Certification course? How long is the In-Class Training? How much does Smart Serve training cost? Is there an age restriction for taking the course?