Unlimited access to all learning material for a flat monthly subscription fee. Unlimited = read all*; Unlimited+ = read and practice all*. Certification need payments per course.
A mastery-focused curriculum builds skills by teaching prerequisites in order, using short daily practice, and revisiting skills through mixed review.
Progress slows down when missing prerequisites stay hidden.
If you cannot tell what a learner is stuck on or what to practice tomorrow, the curriculum is making your job harder than it should.