Is glDisableClientState required?

Question

Every example I\'ve come across for rendering array data is similar to the following code, in which in your drawing loop you first call glEnableClientState for what you will be

Answer 1

Once you have set some OpenGL state, it remains set. You don't need to set it each time you draw.

Manually setting the state as little as possible can be error-prone - this is probably why many people don't do it.