Much more common to unschool for a bit then head back.
Our oldest daughter will be 16 next month. Last year, she decided to take a couple of agriculture-related classes at the local high school so she could be part of FFA and show livestock. This year she spent three hours per day there.
She’s currently spending the next three days at an FFA leadership event at a university about five hours away - despite never having been enrolled as a student in a public school, she will be the only person in her (small) FFA chapter to have ever qualified and attended.
She’s planning on doing “high school” for one more year, then attending our local community college to get an associate’s degree. While she technically “won’t be a high school graduate” when she turns 18, she will have a two-year college degree and about half the transferable credits necessary to graduate from a four-year university if that’s what she wants. For that matter, she could start university this fall if she wanted - but it doesn’t make much logistical sense to send a 16-year-old to live on her own, and that’s not what she wants to do anyhow.
I don’t think there is a true definition for “pure unschooling”. By its very nature, every child ends up valuing different things and making unique choices.
My wife and I are anarchists, and the idea of requiring our kids to attend a government school is kinda anathema to us. We knew about unschooling before our oldest was old enough for her peers to enter kindergarten, so we never really did anything else.
If there’s any one thing we’ve learned it’s that the key is to just let them live life with you. They’ll develop their own interests; support them in that.
If you’re concerned about them learning a specific skill or concept, find a way that it’s required for something they want to do. My oldest learned to read at a conversational pace through Guild Wars 2; my youngest learned basic math through crochet and needlepoint.
Learning is part of human nature. Kids aren’t an exception to that. As long as they have supportive people around them, they’ll learn everything they need to achieve their own goals - and in the process, they’ll learn “how to learn” and build the self-confidence needed to embark on more and more ambitious projects as they get older.
