No you do not. Convential wisdom is to do so however, until you are certain that the transition to the new version doesn’t affect you. This was more appropriate advice in going from say, version 7 to CS or CS2.
But technically, no, you do not need to keep it on your machine.
BUT, make sure you move any custom Actions. Brushes,etc. you might have from CS to CS2.
Thank you guys! I appreciate your answers; and Ed, the moving of the Actions, Brushes, etc. was a terrific reminder.
I almost forgot about that and I was going to loose a lot of good ones right there. Thanks, Domingos