Lines & Sheets
I just replaced all the ones on my boat -- a 78h30 -- for two reasons; (1) I'm moving everything to the cockpit so needed the extra length, and (2) I replaced a jib halyard for a new cruising spinnaker and it looked so nice compared to its breatheren that I just went ahead and did the others, too.Modern lines and sheets are pretty durable and usually last until one snaps or becomes overly frayed. I know the ones I replaced have been on the boat about 6 years in Houston and they'd begun to look a little long in the tooth. I'm sure the manufacturers have a replacement schedule that ensures they continue to sell more line, but I think maybe it's a matter of choice. I don't expect to change the new ones out that I just installed for at least 5-6 years, if that's any help.