Here in NY State you can only have two seperate hooks on a line (per pole). I always fish with the two;
It allows you to offer more combinations and present a variety of options. This helps to figure out what meal looks good to the fish on any given day.
Allows a second chance at a fish, or their nearby friend, if the first hook gets "robbed".
And a double header is more than twice the fun!!!
-reelcharacter