When does the transition from service member to civilian end?

That is COMPLETELY dependent upon what the end game is.  I myself had the goal of my current position.  I retired in 2006 and there were no such positions available.  Took a job within my skill set KNOWING that it wasn't The Prize.  Did good work and bided my time until an opportunity presented itself.  I was able to take advantage of that opportunity and I'm currently doing EXACTLY what I want to do for the foreseeable future.  That took four years.  Up until accepting this position I'd have been happy to admit that I was still 'transitioning'

Hmm, I know it's ongoing. I'm 2 months retired and my ABU's are still hanging in the closet. I think when I start a new job, maybe? When I have a well-established routine outside of the Air Force? Hardest part is losing my daily support group at work!

I agree with you Stephen, going on 3 years retirement and still going through changes and pangs about what I still need to do or regroup on. I think it is a long process, especially depending on how many years you put into service as well, I did 27, so I don't expect it to change overnight or within a few years. Good question.