When's the earliest age you would start homeschooling following a method?

Well, there's Montessori and Waldorf stuff starting from birth. And Charlotte Mason has a whole bunch of stuff written about children under 6. Typically, people start more formal stuff for whenever their child would be registered for kindergarten or grade 1. But you could start with Montessori lessons as young as 1 or 2 (we're talking really short lessons) and regular short lessons around age 3. But these wouldn't be in books.

When the kid asks. It could be four, it could be 14 , it could be never.

Well, a method could be valuable at any time past 3, but make sure you only do as much as you feel is appropriate and comfortable. Yes, this is a precious time in which they are best not to be weighed down by "work". I like that you recognize and value that. Of course, if you're present and open to the boundless opportunities all around you, you'll never run out of teaching ideas, and everything you do with them will be a positive learning experience. Do what feels natural. And have fun!

Its really up to you. Some people buy a formal preschool curriculum, and one major publisher has three levels of Kindergarten; K3 for three year old's, K4 for four year olds, and K5 for five year olds. Other people subscribe to the idea that early childhood should be a time for play, and therefore choose not do any formal academics until the child is between 8 and 10 years old. There are even some people who unschool in such a fashion that they never require the child to any work, no matter what age, unless the child shows an interest and wants to learn about it. Personally I throw together my own stuff for preschool, teaching shapes, colors, counting plastic bears, introducing letters and sounds, and numbers. Then, either at age 5 or 6 depending on when the child seems ready, we start a more formal Kindergarten curriculum. The Kindergarten curriculum I like best is Horizons, it only focuses on Math and Phonics, but I add in lots of reading aloud to the kids, some science experiments (1-2-3 science is great!), and lots of art and music. http://www.aop.com/horizons/

I don't know I personally think you should not miss these precious years. You want your 4-1/2 year old to be more interested in learning? Go to the park, listened to stories on tape, read books, went to the library, baked cookies, read books, planted seeds, read books, wrestled on the carpet, made dorky crafts, did I mention reading books? Pace yourself; Relax and enjoy that "light of your life." Don't be so eager for the carefree years to end.

I plan on homeschooling my kids for sixth grade and on. Public middle and high schools are the worst places for kids, honestly. x

You teach according to your childs interests and ability. Using any particular method doesn't make any difference for infant through grade 2.

Oh, about 12 to 14. Before that they are learning the foundations, not just the basics but a love of learning, discovering who they are and what their passions are. Once they reach those teenage years, that passion will help them learn what they want and need much faster. We are exploring the world all the time, going places, doing things that are outside the norm. Library twice a week, zoos, museums, businesses and festivals...between this my children have learned sooo much, they are ahead of their age mates in school. Likewise, I would never teach my kids to color within the lines....Rembrandt and Beethoven made a fortune and a legacy breaking the rules of their passions.

Really it's quite a natural transition from toddlers to Kindergarten. Children start getting interested in reading somewhere around three and numbers. They also start enjoying games more and more. I found when my kids started fighting it was time to do something organized be it a craft or a reading lesson. I think the best advise is to keep it short and simple. You can a workbook and see what happens. Most kids take some styles of workbooks and not others. The key to preschool is learning how to learn and how to control attention. Then your child will be well prepared for elementary.