As a learner I always leave feedback for my teacher/tutor, even if it's just a quick thank you. If it's a new teacher I leave quite detailed comments, especially if I've enjoyed the experience. In this way other potential students might be encouraged to contact this person.
I feel quite discouraged when I receive no feedback in return, and this has happened quite often recently. If a teacher can't make the effort to acknowledge that some human interaction has taken part, then I'm less likely to book future lessons with him. I don't expect detailed analysis, just a common courtesy. A good teacher will provide useful verbal feedback either during, or at the end of their lesson, I think.