The pattern we see most often: someone books five classes in their first week, feels wrecked, and does not come back.
Twice a week is the pace that survives. Book both slots at the start of the week, at the same times, so the decision is already made when the day arrives.
Pick classes that fit the life you actually have. A seven-thirty morning class you attend beats a six o'clock evening class you keep rescheduling.