What are the TM30 requirements for staying with a friend while maintaining a lease in Thailand?

When staying at a friend's place in Thailand while having a lease elsewhere, it's important to know who is responsible for the TM30 notification. According to the comments, it's generally the landlord's responsibility to report your stay. If you're visiting other islands, your friend or the landowners at those locations should complete the TM30 for your temporary stay. As long as your primary lease in Koh Tao is active and reported properly, it seems that you won't have to file a new TM30 for every place you visit.