How to thank a host who let you crash for a month
Before leaving, ask whether there are costs or chores you should settle. Clean the sleeping area, wash bedding if appropriate, remove all belongings, return keys, and replace supplies you used.
Then say what their help meant. A specific note is better than a vague promise to “make it up someday.” If a gift or meal fits the relationship, choose something thoughtful rather than extravagant.
Keep the thank-you separate from a request to return. A host who offered a month gave a real gift; respect their space after you leave.