italki states that teachers are not expected to prepare for informal tutoring sessions. Most teachers understand it as a session in which a student practices conversation casually and brings questions or work for clarification and corrections. However, given the competition on italki, many teachers prepare topic questions, find materials online, and guide informal sessions far more than can reasonably expected. I like informal sessions to go with the flow, with maybe an article/book discussion to avoid repetition. It's very important to me that tutors focus on the flow of the conversation and that they be good at getting a feel for the student's level & style without a thousand questions.

When I offer informal tutoring, I expect the student to be conversational already OR a highly-motivated beginner who brings questions, written work for corrections, and doesn't expect a fully-structured professional lesson. I bring energy, interest, and happily correct students in writing if they want this during tutoring sessions but I don't work with students who book tutoring BUT expect a fully-guided grammar lesson, extras like homework corrections after class, and are unresponsive during conversation but say they "just want to practice speaking".

My Understanding is that the community tutors don’t have formal training in the language and aren’t really language teachers. They tend to be native speakers available for casual conversation in the target language. So, to utilize their services you really should be at advanced fluency, and not needing instruction in grammar. You should expect the conversation to be conducted entirely in the target language.

The professional teachers, by comparison, normally charge quite a bit more, have degrees or certificates in teaching language and are best suited for true beginners who need structured lessons in grammar and explanation. Also, beginners need instruction in basic vocabulary.