By default, i think Pega passivates the requestors on requestor timeout. This passivated user session is stored in DB or files (and can be tracked via SMA) with expiry time of 24 hours by default? 

May we know a little more insight into how this all happens and more importantly why is the default set at 24 hours? is there a good reason why we chose default as 24 hours and not 12 hours.