How can I get reply messages as soon as they are sent if I want to ?
There will be a option named Watch. You can choose to watch (up to 5) threads. In those threads replies will be delivered as soon as they are sent.
Why number of threads I can watch is limited ?
It helps you to get messages only on threads related to task you are currently working on. So other unrelated messages stays in the Sender's queue until your normal receive time reaches.