Halyard should be carefully inspected each time the flag is changed or at least once per year. White halyard should be replaced at least every 7 years, colored halyard every 2 to 4 years. It's a lot less expensive to replace halyard before it breaks and a lift truck is required. Halyard life is affected by UV, the number of flags that you fly and your winds.
We have a 30' flag pole and live in an open prairie. We get a lot of wind and this rope holds up beautifully.
Had to relocate flagpole ordered the silver color 5\16 rope, very nice product fast delivery