It's really up to you and your needs.   Why would your need for the history be?  Personally three or fours years would probably be ok for my purposes and even then I would rarely need to reference it.

Arguably, the IRS says seven years, but in the case of an audit, I don't think they would be highly likely to looking through the inventory transactions.  Most of what they would look through would be in the a/r history.

However,  I have one client that makes product for the aerospace industry and they have regulatory requirements to be able to trace inventory for more than 10 years.

Thanks, that is helpful.

Hi R Stewart Schow, if this suggested answer helped, please do mark it as verified Thank you!