I offer two lesson lengths on the online scheduler. And of course you can combine them to make a lesson length of your preference. But the ones I typically do are lessons of 50 minutes duration and lessons of 100 minutes duration (1 hr and 40 min).
I have a few different kinds of lessons and a couple programs.
Single vs A Series
You can take lessons in single sessions (one by one) or in packages. I have packages of 6 lessons taken over 8 weeks with a cut rate available through the online scheduler. There is also a more intense series of study called the Semester Program