When we started our older son homeschooling in K we intended to reevaluate after a year. Within a month we were wondering if our adventure was over. It was tough those first years, but every time we sat down and discusssed our challenges, we saw that the blessings were greater. The horizon grew a little farther each discussion. By the end of our second year (younger son entering K) we were all in.
I try hard to be a voluntarist and leave the option for schooling open to my sons, but I have a hard time seeing us going that way now (they would be in 5th and 7th).