Are you sure about that. I was under the impression that if you had a crane cable that was in service for 30 years someone would think about replacing it.
Don't you keep records of replacement and inspections for all were parts? How old are the oldest parts?
Also is shock loading much of an issue?
What is the safety factor engineered in?
Are your parts stainless? The old time riggers say that super heavy iron rigging brushed with tar and oil every day lasts for almost ever and is easy to see if it is rusted and needs to be replaced.
Stainless is much cleaner for sails and decks and can be ignored for months but hides its impending failure better than plain steel that is continually greased.
Your the expert but I suspect that in an industrial setting a 5 year part and certainly a 10 year part just wouldn't even be around. On a sailboat we figure hey it's stainless, looks good and is only 30 years old, lets go sailing.