I use 4 lbs test line for general bluegill fishing! I like 4 and 6 lbs test line for live bait with float (special bobber). I use 2 lbs test line if I have to fish heavy fishing pressure, crystal clear water and bright sunny day! I caught some nice bluegills on 2 lbs test line that fish's mouth is healed from hooked in the past! Sometime you need 2 lbs to fool smart big 'gills but need heavy like 4 or 6 for heavy covers. Not good to use 2 lbs in famous Reelfoot Lake, weeds lakes in Florida, swmap area in southern states, etc! Good idea to try 2 lbs in clearwater lakes in Calfornia! Need long long rod or reduce break line and easier to control big fish on light line!