Let me ask this... do you reference the altimeter in your decision to retract takeoff flaps?
That's why I included option "Once clear of obstacles and comfortable" as a general catch all that is not determined specifically by altitude.
For example when I was training, instructors would forbid me to retract flaps before a specific altitude or to turn before a specific altitude. I don't operate that way in my Mooney. I don't know what altitude I retract my flaps at so I wouldn't be able to give a number. It is more of a feel thing for me that includes being clear of obstacles, having sufficient altitude for comfort, and feeling confident that the airplane will continue climbing despite a momentary loss of lift during retraction.
As to the dentist's point, I don't see it as particularly relevant. I don't think anyone is going to argue to retract flaps while sinking. And most of the points presume you have positive rate of climb in order to be at that altitude or condition. Positive rate of climb alone is probably not a good reason for retraction (such as just climbing out of ground effect).
And those of you voting "right after gear retraction," I'm curious if you could add at what point you retract gear. Cause obviously there's a big difference between retracting when leaving the ground, no runway left behind, and reaching a certain altitude prior to retraction. I'm sure if you go "positive rate of climb, gear up, once gear is up, flaps up" you'd have gear and flaps up before hitting 100ft in most of our birds!