Line Size
The only reason to use 2 lb. test line or 10 lb. test line is for one reason and one reason only: Depth & Speed control. If you look at line in any other perspective, you are kidding yourself.
Over 50 years ago Buck Perry proclaimed this theory of his as fact. And it's been proven time & time again by scores of our most renowned fishermen. If you approach any facet of fishing with those controls in mind, you are well ahead of the game.
Depending on the depth I'm fishing and the mood (speed control) of the fish, I fish different lines and have spare spools set up for just that purpose.
"A voyage in search of knowledge need never abandon the spirit of adventure."