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I would never expect a single load of mono to last a whole season. Even if you don't fish around rocks, it absorbs water and weakens from both that and UV exposure during the day. 20# mono is the right line for a 7500. You'll get two spool fills from a 1/4 pound spool of Big Game or Ande Pink--I'd suggest swapping it out around mid-season if you fish a lot. Compared to what you spend on the rest of your gear, mono is dirt cheap.