Using a testbed helps so you are comfortable working with motors, pulleys, belts, gears, etc. They give you a better view that if they were installed in the robot. New students can learn how everything is connected and you can start your programming tutorials from here. Also if you have students working on the robot and you need to make changes to your programming you can test here and later applied those changes to the robot. It will give you many advantages and we believe that having one is a must!!!!
This is our testbed we connected two motors for the wheels and two for other mechanisms
We connected two servos to test them
These are the two motors that will move the base of the robot
This last photo was taken during the workshop and training at UT Dallas for the BEST Robotics. Thanks to Joel Graber from Dallas BEST & Texas Instruments.