How does the concept of "home" change throughout the novel?

The Jodes never have a home. Their first one is bulldozed to the ground. Then Home simply becomes where they can be together. Sometimes its in a squalid camp for itinerant workers or a better government run camp. In the end the concept of "home" is elusive. Ma Joad tries her best to define home as togetherness. The horrible conditions force characters like Tom and Rose of Sharon's husband to re-define it in some future tense that they are yet to find.