My company is developing guidelines for employees to document their work so that in the event of an external audit there is a clear trail of what was done. So, just as bench scientists fill in their lab notebooks, we bioinformatics folks are expected to record our work in a "notebook". The question is: what is exactly worth documenting? Should every minor change in a script be recorded? Or should a written summary of what tasks a given program accomplishes suffice? I would like to hear about your experiences in documenting your programming/data analysis work.