For me, if you are a beginner to intermediate students (A1 to B1 ) , it is a good idea to stick to one teacher at this time. Of course a teacher who knows your objectives and your learning style and based on that he /she plans lessons accordingly. But if you are advanced (C1 to C2 ) and you only try to focus on developing your speaking skills, I think that you can have more than one teacher. Good luck and sorry for the late reply.
