Actually, there are no strict rules for using a specific number of scales in the Likert scale. Whether you want many or few, even or odd, there's no prohibition, but there are indeed advantages and disadvantages.
Wait, what? Isn't one of the main sources of research what consumers say?
That's right. When we conduct research, we get answers from consumers based on our concerns. However, we must keep in mind that we need to view their answers by also understanding why they answered that way.