Production retention period suggestion IDOC and Asynchronous messages

Dear friends,

I would like to set up retention period in production environment in PI 7.4

1) Could you kindly provide me number of days of rentention you configure in genera in productionl.  Could you please suggest what values are i have to provide.  I was considering 10 days.

          a) xiadapter.inbound.persistDuration.default

          b) xiadapter.outbound.persistDuration.default

2)  For IDOC persistance, in production can you sugges pros and cons activating  below parmeters apart from fast processing. Atleast i feel this will help us easy to determine based on idoc.

persistance  in the resouce adapter ->  JavaIdocAdapter  ->  Persistance   :   True

Could you please suggest if I missed anything from the persistence and rentention period in production environment.  Any suggestion is appreciated.

Thanks