Do you need to change the copper washer if you have changed them out two or three times?

yes..replace them every time..and replace the o-ring on the connector tubes also...i got lots of them!!

Well white is right is "should" be change everytime but I've managed to re-use mine a few times now with no problems. The copper washer is a multi-purpose piece... 1. Adjusts spray angle height.2. Conducts heat away from the injector into the water jacket.3. Seal for the compression gasses. So after using them a few times it might crush a bit changing angles and sealing abilities...