When it comes to involvement as a grandparent,how do you balance in laws vs your own parents? Is it fair to assume that whoever is not working has a greater responsibility?

Honestly, neither side should have any "responsibility" when it comes to my children. My partner and I don't expect much from them but will appreciate any help they choose to give. Grandparents' involvement should be more on the leisurely side, I feel. If they have too much responsibility, they might also want a say in how you raise your child -- which is okay if you agree but when there is an issue that you don't agree with, it can be quite messy.