I learned the change your line lesson the hard way. A few years ago, I pulled out my worm rig before a tournament looked at the line and decided it needed changing. I set the rod on the bow, and went to do something else. I looked at it for 5 days, and ended up not changing. That night it cost me and cost me big time. I broke off 5 good fish on a night when fish were slow. The 5 I broke off would have easily won the tournament, fact is, 3 of them would have. From then on, I change mono before every tournament. Sometimes, I will prefish 3 or 4 times on the same line. It depends, is money on the line or are we just having fun.
Skipper