I left my job as a public school administrator to homeschool. You can imagine how many head-scratching questions, eye rolls and dirty looks I got for that!
Our tipping point emotionally was earlier, but our actual decision making tipping point was when I was spending more time at the school advocating, volunteering, fighting, arguing, photocopying and teaching teachers than it would actually take me to homeschool. That was the final "Why are we wasting all this energy when we could just do something else?"
