So how long is too long

Our family has been homeschooling for 8 years now. Justin is in 8th grade, Jared is in 6th and Jessica is in 4th. How long is too long?
You know I have honestly asked myself this very question many times. Every year around the same time, the end of the school year. I wonder all the time if I am doing what I am supposed to do. I guess you could say I am keeping myself in check. I don't want to homeschool because everyone else is doing it. (well they're not) I don't want to homeschool because I don't want my kids in public school. I don't want to homeschool because my kids need me. I want to homeschool because God called me to it. It will be until I feel God calling me out of homeschooling, I will stop.
Homeschooling has taught me so much. I am not talking just academically. Yes, I have relearned and understood so much more since I began homeschooling, but I KNOW my kids better than anyone else. I know how they learn, what makes them tick, what makes them excited, what makes them learn, better than any teacher ever could.
It makes my day to hear and see the excitement on my kids faces when they have mastered a concept. I taught my kids how to read, write, add, subtract, divide, and so much more. They can communicate with adults and play with a variety of different aged of children.
One day Andy and I were cooking supper together and he mentioned how nice it was to hear the kids playing together. He said by the time he was Justin's age, 13, he and his sister rarely communicated. He loved hearing our kids not only communicating, but playing and still using their imaginations together. Yes, they still argue. Do you know of any siblings who don't? But for the most part they love being together.
We all need a break every now and then. Yet, I miss them all the more. Andy said I will probably have a harder time with the "Empty nest syndrome" than most. We'll see. I say no way. LOL
All I can say as like any human I get tired of it all. Yet, I love my kids and will do my best as long as I have the support of my family, but most importantly my God.
"Train a child in the way he should go, and when he is old he will not depart from it."
Proverbs 22:6