I read one theory that for approximately every five years as a JW, a person would use 1 year to process and obsess before tapering off. There was no real validity to the theory, but it was one person's thoughts. Still, it made me think of myself in the way you, Jeff, are thinking of yourself- when do we move on? I faded in early 2007 from close to 20 years of involvement. I can see my ex-JW involvement dying off soon. The 5-to-1-years theory might work on me- sort of. I think AK-Jeff, one of my good buddies, is already crossing over to "former JW" from ex-JW.
It all depends on so many things. I have an active JW wife and mother. I am on the verge of moving on, but my wife's day-to-day involvement reminds me of my past and I wish for so much more for her. If my mother were to pass, it would change things slightly. If my wife were to leave the JW's, it would change my whole world.
Many have adult children in the JW's or parents in the JW's or mates or young children even. Some have entire families out of it. That's one huge factor.
The next factor is personal reasons for joining, level of participation, how duped you feel- stuff like that. If the United Nations and Malawi and changing doctrine are your thing that gets to you, you might be an ex-JW for awhile longer than someone who just didn't care to be controlled and got out. If you were burned in some way or thrown out, you may stay an ex-JW for awhile longer than others. So many variables.
I needed God to personally come to my rescue and be the only entity in the universe that cared about me. Then I needed to know "the truth" if He did come and rescue me. Doctrine was everything. But letting go when doctrine didn't add up was because of the primary reason, that I needed God to care about me. I wouldn't let go for a long time. When I did let go, I was bitter. When I found out that the doctrine used logic fallacies, I found myself losing my God and losing myself (doubting my own ability to think for myself) and at the same time, my mother asked me not to DA so she could speak to me. Add my wife's continuous involvement and absolute refusal to really discuss WT's problems and you have a long-time ex-Jehovah's Witness.
So when I feel my involvement dying off within a year, I will always have a higher level of interest in ex-JW stuff than many walkaways.