How often do you change up braided line?

On spinning reels, every year, but I never use backing so after one season I'm down enough line that I need to change it out to keep decent casting distance. Don't forget my "go to rod" is used hard 75-100 days a season. Constant, repetitive casting causes the smooth surface coating to wear.

On the conventional reels, once every 3 years or so. These rigs get 1/20th the use of my spinners...

I don't do a lot of casting like Roccus, but his suggestion on Spinning reels that see a lot of casting use makes perfect sense.

Most of my fishing, whether using conventional or spinning reels is done just dropping down for bottom species so I do use backing on my tackle. I also stick to about a 3-year interval for replacing the braided portion of the overall spools and that is after the very frequent use my tackle sees in a charter operation.

Like most things in life, you get what you pay for, so if you want to get that type of lifetime from your braid it pays to buy the premium stuff. There have been many excellent articles written by Lep on his Tackle and Techniques board so I would suggest reviewing a few of them for recommendations on top brands.

On spinning reels, every year, but I never use backing so after one season I'm down enough line that I need to change it out to keep decent casting distance. Don't forget my "go to rod" is used hard 75-100 days a season. Constant, repetitive casting causes the smooth surface coating to wear.

On the conventional reels, once every 3 years or so. These rigs get 1/20th the use of my spinners...

I forgot to mention why I don't use backing. It's pretty simple, in my world there is the odd chance that I could find myself hooked into a BFT. For that reason, I don't want a knot on my reels that could hang up as it goes screaming through the guides while I'm stumbling around trying to start the engine to begin the chase.

It's a Fire Drill I've yet to experience, but as a firm believer in Murphy's Law, I'm still hoping...

Backing serves a couple of purposes: protects the spool and allows you to use less braid to fill up a spool.

I'm not much of a spinner user (my spinning rods all have mono) but with conventional reels you'll save alot especially on inshore reels.
That said, I change my braid every 2-3years depending on use.

Spinning reels for chucking plugs - 2 years. I tend to overfill the spool. I know wind knots - only if I get sloppy, and that has been a long time even using reels without a bail. I cut a bunch back.

Spinning reels for dropping down - fluke and tog etc - overfill and 2 years

Conventional - fluking and other bottom - two years

Conventional - bass in bunker schools - overfill, cut back, change yearly. Too many times I feel fish hitting the line. And after a bunch of sharks this year, just change it.