How often do you replace your fishing line?

I have a few reels that the line (Berkley Nanofil) is several years old.  How often do you guys replace your line?

I mostly use braid now so I don't change it all that often.  I use fluorocarbon leaders and those I change more often, but we are talking a few feet of line.  Can't say I ever really broke the braid off before, pretty much always the fluoro, so I don't have much of a reason to change the line on the reels.  I tend to use heavier braid on the reels and lighter leaders.  I do have some that looks old though, I may change that just to be safe.  But I bet it was on there for 8 years.  I even use braid for my slip bobbers, with a fluoro leader as well.  Up front cost is more but less maintenance.

I think its more important to cut off about 5-10 feet of line every so often. That the line that takes a beating. I also watch my line carefully when using certain setups, such as a bottom bouncer.

I replace the mono line on my most used reels every spring and when the line gets low once again about july/august.  The braided line on my catfishing reels i replace whenever it gets low maybe every 3-4 years.  I keep my partial spools for leader material so i don't have to cut much off the spool in a season.

A wise man once asked me if the hassle of respooling your line every year was worth not losing the fish of a lifetime. Since then, I re-spool more often than likely needed. Because why not?

I ice fish every weekend of the season and change my line usually twice in a season. I open water fish about 3 times a year and still change my line every year. Someday I'll catch that fish of a lifetime.

Pimplyswede, I fish 2-3x per week.

Mono: Whenever the spool gets below and 1\8th" or so on spinning rods. I pull off about 10' several times a day and retie. Fresh mono fishes so much better. I'll go through ~1000 yards on my trolling rods in a season.

Braid: I can get 2 to 3 years out of it. More on the 65 to 80lb stuff. I turn it around on the spool when it shows wear.

Keep it all out of the sun when not in use. I guess my point is I changer my line as often as needed as opposed to trying make it last. I don't fill my spools with the line I fish with either. Always use a generous amount of cheap backing.

I fish open water 40-50 times a year. I use Trilene Big Game ten pound test. I can fill all our rods for $8.

Monofilament often, depends on how often you are fishing, but at a minimum once  a year.  Braids can go longer.

I also have reels that have mono anywhere from 2 to 10 years old.  When I tie a new knot and it busts, I grab a different rod, and replace line later on the one that busted.

Perhaps if I fished every day things might be different, but the rising cost of everything has me being frugal.  I can't remember the last time my line broke and it wasn't because of sharp teeth.

Those of you who replace 2x/year - how often do you fish?

I mostly slip bobber and troll/drift. The mono on the slip bobber rods I change twice a year. The power pro on the drifting rods, probably never. The reels sometimes wear out with the original line on them. 

My braid rods all run a 6ft flouro leader so i only have to change that line every couple years because there is not much cut and retie with the actual braid. My flourocarbon gets changed yearly or more. Depends when it starts to cast bad.

All of my rods with braid get re-spooled probably twice a year. Mono and floro probably once every other month. Trolling rods with mono get replaced when my baits aren't running to the desired depth (usually twice a year). This is due to break offs or frays in the line or nicks from weeds, rocks, or other structure. 

I always have a backing on all of my reels so I'm not filling up a spool and only using a quarter of it then pulling it back off.

I might add that I fish rivers a lot and also in waters with a lot of rocks and trees/wood. I fish open water all year so my gear gets more of a work out in a year than most guys' gear will see in a lifetime. Nothing gets me more upset while on the water than losing a fish due to line failure.

A bit of advice when spooling braid. I seen this on a fishing show this spring. If you have trouble braid twisting, with the line spool set vertical try spooling the line from the bottom of the line spool and not over the top, the guy on the show says it works but he couldn't explain why.

I wouldn't replace Nanofil unless it started to frizz,same with Fireline.Mono and such,I replace when needed.Once a year,unless it has seen abrasion or excessive sun exposure.UV kills monofilament/fluorocarbon lines faster than you think.Like those guys that leave their rigs in boat,exposed to the sun for days. 

I replace line every spring and as needed throughout the year but I always leave 1/2 spool of the "old" stuff on the reel as backing.  Don't have to buy so much line that way...saves a few bucks when changing line on 12-15 reels every year.