- Change your bow string annually, or sooner if it shows signs of heavy wear.
- Re-serve everything and tie on a new d-loop annually, or sooner if either shows signs of heavy wear.
All depends on how often you shoot, what string material you're using, what arrows you're using, how you store your bow, and a host of other variables. My dad has a Mathews Featherlite that wears a 10 year old string. It stays in his closet at camp and gets shot maybe 5 times a year. It's his backup bow in case he forgets to pack his main when he rides up for a hunt. He had me check it out last year since I have a press. I pressed it, separated the strands and fibers, checked the serving, shot a few arrows through paper, waxed it, and gave it back to him.
If you are someone who likes or believes in shooting a hundred arrows a weekend all year, annual might make sense. Strings are tougher than folks think they are. I can't tell you how many perfectly good strings I threw away when I worked at a shop because somebody thought they were being smart and doing the right thing. Heck, a lot of times all they needed was new serving. Bit nope, gotta have a whole new string to the tune of $150 bucks.
You'll be uncomfortable with a string long before it breaks, barring a freak occurence or something like a burr on a cam groove cutting it in a dozen shots after you ding the cam without realizing it.
Bows are tough. Bows are simple. Bows have a lot of myths and rumours surrounding them. Like heat delaminating them. I used to get a kick out of telling people who insisted on that little legend that every one of the 400+ bows in my shop came from a warehouse in atlanta in a big, metal, shipping container around july or august. So hot when you unloaded it you felt like you were opening an oven.
There are many things in life worth worrying over or babying. Bows ain't one