Minnesota requires 16 hours minimum of continuing education by a state certified instructor for renewal every two years, and I have heard rumor that they are discussing the possibility of upping it to 24 hours.
Other states that I know also require CEUs are North Dakota, South Dakota, Nebraska, and I believe Wyoming. There are more of course, but I'm not sure which ones.
My company began hiring a private instructor for all of our electricians (licensed and unlicensed). I can't begin to tell you how much good has come out of it. The class that this instructor teaches can be tailored to the employers needs, and is valuable beyond imagination. He uses a lot of visual instruction, and keeps the entire class involved and on the edge of their chairs. The instructor is one of the very few "fulltime" code instructors in the USA, and is possibly THE most knowledgeable person of the NEC that I have ever met. You can view his website at
www.electricode.com I attended one other class that was almost worthless, it was taught by a state electrical inspector. It was hard to stay awake after the first five minutes. So I feel that if you can get a good instructor, CEUs are invaluable, but a dry boring one makes for a waste of time.
Matt