Some homeschoolers are very structured. Some homeschoolers structure their lives on the open classroom models used in the early 1970's. They were big in many New Mexico school districts, so some of you reeading this might have taught in one, or attended one. This is a structure based on removal of the traditional structure, on interest-based learning, on discovery learning. I'm an unschooler.
Lessons are never over.
On the other hand, lessons never really begin. Children's question are answered and an atmosphere of learning is created so that questions are constant and answers are never far away. When you ask an unschooling family how much time it takes to homeschool, first there's a pause. Their range is it takes from zero hours a day to 24 hours a day. When learning is recognized in the fabric of life and encouraged, when families make their decisions based on what leads to more interesting and educational ends, children learn without effort, often without even knowing it, and parents learn along with them.