My wife has worked as a teacher and has a related degree. Out oldest daughter went to a private preschool when she was three and quickly became bored with what they were teaching. We learned that the same curriculum would be covered in their four year old class so we decided to start homeschooling at that point. She is currently seven years old and is working on curriculum that is beyond what her nine year old friends are working on in public school. She has more friends than I did when I was her age and they are of a wider age range. She has played soccer, takes dance classes, attends church, and and we meet monthly with a homeschool meetup group.
We also have a four year old daughter who is working on similar curriculum to six year olds in public school.
We homeschool primarily for academc reasons as we have seen the horror that is "common core" and the waste of time that is "no child left behind". We have taught Astronomy, Robotics, Weather, and Bird Studies so far so we aren't just teaching the basics.
We live in Texas which has some of the most homeschool friendly laws on the books. Homeschooling falls under the same statutes as Private Schools. There is no attendance reporting, no mandatory testing, no approved curriculums.
The requirements for homeschooling in Texas are as follows:
The instruction must be bona fide (i.e., not a sham).
The curriculum must be in visual form (e.g., books, workbooks, video monitor).
The curriculum must include the five basic subjects of reading, spelling, grammar, mathematics, and good citizenship.
The State of Texas assumes that if you care enough about your kids to want to teach them yourself that the state will just get out of the way. The Texas Homeschool Coalition holds conventions every year were we take seminars and shop for curriculum.