We will always continue to buy DGC presents, BUT, we have a budget. We are comfortably off and only have 2 grandchildren, so the budget is £50. They are still at the point where we buy things, but we are starting to move to tokens for birthdays. Zara tokens go down very well with DGD. If you have less money and more grandchildren, the budget could be as low as you like.
As for them giving you nothing. We EXCHANGE gifts with our DGC and if they didn't give us something, even if it is only somethig small and trivial, and say thank you, they would get nothing.