When is the right time for a Post Doc. to start applying for a lecturership position?

I normally come across many advertisements about lecturership positions in different universities all around the world. And I always wonder when is the right time for a post doc. to apply for it? As, I am never sure that my experience will be enough for the position.

What are the necessary ingredients of a post doc.'s CV, that should help him getting such position?

In general, these ingredients can be found in the ads. as a vague statements like, extraordinary research experience, record of publications, etc. But what is the quantitative meaning of the qualities or does it just depend upon the applicants that applied for a specific position and their qualifications and achievements, i.e. a relative quantity?

We have a large number of mechanicians in this list who are part of faculty of different universities. It would be great if they could shed some light on it, based on their experiences. 

Thanks in advance.

 Amir