Mentoring relationships can seemingly go on forever if there isn't a discipline of checking in against some objectives. They can fizzle out or become more like chats and that's not the lasting impression either of you would want to leave. 

If you’ve volunteered for a mentorship programme and been matched with someone, your first meeting will be a 'get to know you' session. This is key because, like any relationship, you need to find some mutual ground early on.