Taking good care of a Jack Russell Terrier is virtually a fulltime job at least while they are awake. This little dog probably has more energy than any other dog you will discover. This energy needs to be channeled in a positive direction because if you keep them confined they might become destructive or even extreme toward humans. Find out more about jack russell via britishgrit.
A good strategy to channel this energy is by means of training. Jack Russell's are very smart and can learn quickly. They will learn a lot on their own which may not be what you need so interact with them whenever you can. They are a good family dog as there will be more people to help burn off their energy.
Because the Jack Russell Terrier was bred as being a fox hunting dog it likes to play at hunting which translates into running and playing. They especially want to be around children as they usually have as much energy as your four-legged friend terrier. Older children will be able to train it to do many tricks including retrieving objects. This can occupy both the pet and your child for years. I've seen a Jack Russell Terrier push a soccer ball around with its nose for hours on end waiting for someone to play about it.