During recent family visits I discovered that 2 of my cousins operate sawmills separately. One of them also has a kiln, I think he said that 7% moisture is the usual target.
What happens to wood when it is kiln dried?
He said that the windows in the original farm house, 100 plus years old are still good, but the ones in an addition that is only 60 years old had to be replaced. He blamed the early demise of the new windows on them being made with kiln dried wood.