Im not sure without actually looking; but fishing line definatly deteriorates over time. It gets hard and brittle, breaking strength is way less then it was when new. Unless its braid, I too change mine twice or three times a season. Id hate to loose a trophy fish due to line failure.
I'll change mono after 2 days of fishing, but braid lasts a while which is what i only use now 50lb for baitcaisters 20 for spinning keep it simple stupid
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