The whole thing of parents helping out with the kids and giving them all the expenses is not undesirable in my opinion.
The parents worked hard to bring you up, should have received a pension to enjoy the time, to come to see the child for you, it can be said that they are going to treat you from childhood to adulthood to go through the process again.
This deprives many parents to be able to idle down, quietly enjoy the freedom of happy time, if the parents to you to ask for expenses, you should symbolically give parents some pay, but also let you understand, pay to be rewarded.
Of course, if my parents help me to bring up the child to ask for fees, I will say to my parents "yes, no problem", after all, you did not see the child so hard, I will give you to buy a little health care or other massage chairs and so on.
You can also give your parents some practical things in disguise, so that they can be happy.