Is there an ideal schedule for open learning?

Yes, the ideal schedule is the one the child co-creates with his or her family. Rather each member of the family plans, discusses with others and using reflective inputs from others continuously fine tunes their open learning journey. Obviously the plan / schedule / structure of any open learner is very dynamic as the needs of the child / learning and family keeps changing.
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https://aarohilife.org/home/blog/sdl-aarohi-home
https://aarohilife.org/sdl