CFII  

I have done the free renewal every two years with American Flyers  for over 25 years. I agree is is kind of a pain but it keeps me sharp on changes in the industry that I may not have been aware of otherwise. Flying part 135 the CFII is not really necessary as it's not needed to be a company instructor. However It was mentioned at my last interview and I believe it helped me get the job. I see it as insurance should my current job go away I can still teach while waiting for somthing else to come along. I also may use it in retirement to do some teaching at the local airport. YMMV.

https://americanflyers.com/training/firc-for-life/