Any Ideas on recommended IIS cache settings for RoboHelp 11 WebHelp?

How important are the updates? And how much load can your server handle? If you regularly update and everyone needs to see the changes immediately, set the cache to 0. If you publish every month, a week or perhaps two would be ideal.

Note that if you cater to mobile devices using a mobile data connection, setting a very low cache will slow down your help as they will need to retrieve everything whenever they want your content.