We will always show you all of the teachers you've had a lesson in the past with. If you do not see a teacher listed whom you've had a lesson in the past with, they are probably not teaching with us any more (but note - if you took a lesson with a teacher in one account, e.g. your wife's account, that teacher won't necessarily show up in your own account if you've never scheduled with them in your own account)

Teachers change their availability from time to time, and their schedules get full; once a teacher's schedule becomes nearly full, we do not show them to you (unless you have had a lesson with them in the past)

If a teacher becomes more available, we will start showing them again