Any ideas on the shelf-life of mhrb shredded or powdered, will it deteriorate over time if kept dry cool dark ?

Sorry Im sure this will have been covered but I tried the topic search but didnt get anything
any pointers appreciated

The FAQ is usually a pretty good place to start in most cases, including this one.

It's towards the bottom, DMT/Plant Storage.

Seems like it should be good for quite awhile. I'd say keep it away from extreme heat as much as possible though.

Thanks for the pointer M C

I have stuff that has been powdered and sitting in my herb cabinet now for about a year in a big bag and is has not lost any potentcy.