Hello Richa,
Good move, Extended Notifications is great.
I like to keep things as simple as possible, so just one subscription. If I can, I also don't list any TS tasks so that new (or changed) ones get picked up automatically.
There are no special precautionary measures for Prod that I can think of. Just make sure you test it very very well in Test, for example by creating a workitem, waiting a day and then making sure that when Notifications are turned on the next day it does NOT pick up the old one. There used to be a problem with this but I haven't seen it recently. In Prod that one workitem from a day ago can turn into 100,000 from last year.
Good luck and let us know how it goes.
Rick
