Hi Alan,

Peronally I would say modified date.   But, it would depend alot on the type of working environment you're in?  For example, are you an insurance company, with users that have alot of old policy documents that they view on a daily basis?  If so, setting the Last accessed option would not archive those documents over 1 year old, and that could be literally thousands.   Have you run the FSA reporting tool in your enviroment?  It gives reports about the type of files you have and their age etc...

Thanks,
BZ

Hi There

Thank you for your comments.  I am refering to the File System Archiving.  The business is a Local Authority and is quite large in terms of data storage. 
At the moment our pilot is just to archieve data on last modified, everything that is over one year old is archieved and if it is modified then stored back into it's primary location, this in my opinion is the best way forward as it means that although there might be a lot of data moving backwards and forewards it does mean that more data is archived in the long run, i suppose the only real way would be to test it...
I am not too sure if the FSA tool has been run, our IT is contracted out to a third party company i'd have to check with them.
Thanks for your help everyone.

Cheers
Al

Hi Al,

The utility's official name is the File System Analyzer.  It runs against your environment and reports on files type, size and date.   It helps when you need to make design decisions like this based on factual data from your environment (a bit like exchange store reporter for your mail). 

BZ

Thanks for you help everyone.

Regards

Alan