I've always found that the job search becomes much, much harder after you've reached 4-5 years of postdoc. If you aren't successfully interviewing and getting interest by your third year of postdoc, you could be in trouble if you don\'t start getting some action.
I don't know how to advise you on the question you posed about staying too long in the one lab. But going by years, if you are approaching 4 or 5 years, moving now to industry would be a very wise idea.
Employers start talking about applicants being "too academic in nature" once they've postdoc'd too long,
Dave Jensen, Moderator
"The moment we believe that success is determined by an ingrained level of ability as opposed to resilience and hard work, we will be brittle in the face of adversity" -- Joshua Waitzkin