A lot of customers turn this on because they want to add the activity formatter to track updates to important fields etc.
However, if you have a feed which is constantly updating fields, or you are fed up of last login time populating every time someone logs in, then add the no_audit=true attribute to just those fields.
That way you audit fields you care about, but not ones you don't care to or are automated updates etc.
i.e. I want to know who changed my name and when they did it, but not when I last logged in or some other non important action.
plus those fields clog up your history and make it hard to see the important items.
