This happend to a friend of a friend
A guy booked a lesson with Joe H.
He steps in mr. H's house, and they go to the music room.
"Warm up, tune your horn and I am back in a minute"
After 40 minutes of warming up on the flattest piano on earth he adventured in the house, looking for the teacher.
Mr. H is watching TV.
"OK, I come, let's play a blues"
Mr H sits on piano. After the blues, mr H. says:
"Wow, you are great. wonderful solo, Man, you are burning! 50$" (back in the 80s)
Thelonious Monk had lessons with Art Tatum, in which Mr. Monk was too shy and paid Mr Tatum to play in front of him. (Monk was already famous)
Any advice can be precious. Don't expect a piece of paper with an exercise for next lesson.