Longevity of covered Dyneema halyard?

[SailFastTri]

My main halyard is Dyneema core covered by tightly woven medium blue Polyester.

The cover is in great condition, is tightly woven (little or no UV penetration) does not appear faded or worn... but a rigger advised me to change it due to age (it's 20 years old).

I have cut a few feet from the end every 2 or 3 years to refresh the knot and move the full-hoist sheave compression points.

Is this rigger just being conservative? Should I take his advice? It would be over $700 to replace this line which appears to be good.

[psk125]

We had a cored jib halyard fail on us - can’t remember if it was kevlar or spectra. It broke at the sheave despite the cover looking fine. With line as old as yours, even moving the turning point each season may not be enough to forestall a failure, but who knows? Yes, the rigger wants to sell line, but isn’t the halyard getting a touch short at this point anyway? It may be time to bite the bullet on this one. To reduce the teethmarks, perhaps you could have a cheap tail spliced to the Dyneema. You don’t need two mast-lengths of dyneema - you only need one and a bit more to allow for reefing. The tail could be any double braid you have available - the only load on it would be the weight of the sail being hoisted, until the dyneema took over the load with the sail set.