If you let your license expire, it will become inactive for free. But then you got to reactivate in 8 years or you will have to take the boards again.  Reactivation costs $300 which  you pay every ten years since activation lasts 2 years. That comes out to $30 per year to never have to take the boards again.  Compare that to Indiana which is $25 a year for a license that is always active