At a busy, complex unit there might literally be hundreds of supplementary procedures published every year, hype they permanent, temporary or perhaps just information to be promulgated.
Our local rule book, the MATS Part 2, is usually published twice a year, so towards the end of each six month period, the four hundreds page document might be modified by well over fifty or so procedures that have been introduced since that edition of the MATS Part 2 was published.
Keeping on top of all the procedures is one of the more challenging aspects of the job.