Depends on what you want to do. If you do locums then you want to keep your license active. Its easier to put into an inactive status if you don't use it than let it expire. If you let it expire then you have to start all over again with applying should you ever go back. to that state. A real hassle in some states that can take up to 10 months to get a license (Texas, Oregon, Nevada, Alaska).
I had such bad luck with permanent jobs that I always figured I could get a quick locum job with an active license should I quit or get fired suddenly (happened to me 5 times in 5 years)
Even to this day after 4 years on my permanent job, I still keep my other licenses active because sometimes I still do locums in those other states on a short vacation coverage job.