Our kids have wanted a dog for years. We finally gave in, but only after extracting promises that they would all help us take care of the new puppy.
In our realistic moments we knew that it would be mainly the parents looking after the dog.
Two months later and it hasn't been so bad, the kids do help with some dog chores and Buddy is a pretty low maintenance dog. It hasn't been anywhere near as much work as we thought it would be.
There is a good article on the Pookinuk website about why pets are great for kids too.