I purposely didn’t replace or wax my string for 13 years just to see how well or bad it frayed. When I replaced my string it appeared fine although time to replace. My cables had a few threads severed supposedly but they looked fresh clean cut to me by the jerk who refused to put them back on all because he made custom strings at $140. That shop fell apart soon after because of him. Later I went with another shop using vapor trail and like them but that string came off a year later because of my fault holding the cam with my hip and severed half of that string.
I won’t recommend waiting near as long as I did but I hate changing strings due to accuracy and retuning. I did keep it in the case and under close watch when out though. Every two years is just playing it save imo. Now my friend makes strings with a passion so I’m liking his work best so far. I don’t plan on waxing this one more than once either. Four years should be where it’s at I believe. Every year not for me. Just visually inspect often. Remove with a press once a year and inspect. Your choice.
As long as you keep it waxed, no cuts or frays, kept out of extreme heat, keep a check on the servings, middle and ends. If the bow will stay within specs i.e. ATA & brace height most can get 5 years out of them. Especially if you don't shoot that much and swap out for a gun as soon as you can. A lot of places just want to sale strings and buss cables, $2 worth of wax, applied properly, goes along way.