Replace it now
Hello,The good news is that the boat has been lightly-sailed in a mild, low-salt climate. The bad news is that other factors (state of tune, original quality, scantlings, accidents) can be at least as rig-degrading as use. In addition, the load cycles the rig experiences jsut stitting at the dock have, over all these years, contributed to fatigue.You don't wait until your engine seizes up to change the oil. You don't wait until your boat is filling with water to inspect the through hulls. And you don't wait until you're knocked down to reef. So why wait until your wires are actively breaking before you replace them?Fair leads,Brion Toss