9. Leave the Place How You Found It
If you’ve been cleaning up behind yourself during your stay at a friend’s house, then leaving the place how you found it shouldn’t be a problem. But take it one step further and do laundry before you leave. Strip the sheets you used from the bed and gather all towels and wash cloths and wash them. It’s one less thing for your host to do and s/he will appreciate the little bit of extra work you’ll save them.