Since legislation and engineering are subjected to continually evolving practices and procedures it is mandated in "FDA 21 CFR Part 820 Subpart B, Sec. 820.70", that such changes must be integrated into incumbent equipment using company approved and documented methodology. Simply put this means that we write documents for the situation as it appears right now and this is controlled by date and issue number of each document.
The purchasing of a registered document entitles you to use the document as often as you require. After recurrent use, we would expect you to check that it is still the current standard. Shortly we will be incorporating into our site a reference system that will greatly expedite this task for you; currently, people email us.
The document you purchased today could still be current in weeks, months or years. However, it could be re-written within a few weeks if the requirement arises. Out of date documents cannot be updated – a current issue level document must be purchased.