Depends on the brand of line. I have had the same Pline flurocarbon(NOT CLEAR) on my reel for about a year now. Other lines I might change after everytrip (Usually stren, that stuff is crap thats why I stopped using it).
Boy I dont know ,if I had to change my line after every trip I would be bankrupt!For mono I change mine once or twice a season,for superlines I think thier good for atleast a year if not more.I tend to run low on my spool more than anything.
This depends a lot on what kind of fishing you do. Cat guys tend to fish places that cause a lot of nicks and abrasions on their lines. Trollers on Erie rarely stress their main lines with the exception of drifting debris or tangled lines.......they may however change leaders regularly. Perchers using good braid may use it for years.
My braids for trolling are lasting a couple years with only reversing the line after one year. Mono lines gets changed at least 2-3 times a season.
At least once a month if not more. Depends on how much I am fishing and the cover. Braided line usually lasts a little longer for me. But Mono I change really often. I buy the 1000+ yd spools every couple months...
my two baitcasters 14 lbs. bps excel clear blue mono line i change about every two weeks when fishing 3-5 days a week, less than that once a month, i fish alot of cover and will put my baits right into the thick of it all so my line gets beat up pretty good, my cat poles i use bps excel mono on too and i change that once a year.
the worst thing that can happen is have old line on ur reel and know its old line and have the line snap on a really nice fish!!!!!!!!! i know we all have been there before!!!!