Ideally, you should have enough identical kits, so that each member of the family can easily access one: at home, at work or school and in the car. At a minimum, you should have at least one kit in your 'safe room'.
Everyone in your family should know where to find the kit, what it contains and how to use it.
Family emergency drills are an excellent way to familiarize everyone with use of the survival kits (they can also be fun and a great psychological help if a real crisis ever occurs). You should run a drill every three to six months.
It's important to periodically change the food and water of the kits with fresh food and fresh water. Like food, stored water doesn't keep for ever. Rotate your stored tap water every six months. Mark the fill date on each container so that you know when it's due to be updated. Empty the containers, clean them as explained above, and refill them with fresh water.
Your family emergency drills can also be an opportunity to consume outdated supplies before they are replaced. You should also check that all the other contents of the kit are in good shape and functional.
If you family doesn't practice with you...how will they take care of themselves if you are not there?