If I am photographing my kids and taking a simple portrait, I like to have just enough of their face in focus and blur the background. This ensures that the photo is all about them, not the greasy handprints on the wall behind their head, the dishes I left out on my kitchen sink, or dirty socks on the floor. You can take great portraits inside your own house and get that fun lifestyle element without showing too many details in the room behind your subject. You can also tell a fun story by using a shallow depth of field.