Child Support Increase from spouse

My ex and I are both in the teaching profession. We, fortunately, receive pay increases each new school year. I am wondering when, and if, I should have Domestic Relations review the case.

If he has a pay increase, would it be worth a review, but I also receive a pay increase. He makes much more than I do.

Also, if our child begins preschool this year, do I have a right to ask him for additional monies or does the child support he pays now, take care of activities?

thanks