I've got 33 years in now. Things have change enough the last few years it is no longer fun. Eligibility for retirement is about 30 months away. 5-10 years ago, I was saying I was going to put in 40. Now I'm setting things into place for another career to step into for 10-15 years. More if I'm having fun.
I can't complain too much, as my current career has been good to me. I'm just tired of the environment that I'm working in. Most often day is trying to get people to do their jobs. If they would do it correctly, I wouldn't even have to get involved 90% of the time.