Not exactly an impartial source.
You: You think I should spend my money on your equipment, even if it seems to be in good shape?
Vendor: Hmmm... let me check my bottom line. Yes! Change it all at once! And those chain plates as well!
I know, I'm joking, but my point is that if a reputable expert, who stands to gain financially (implied), thinks it is fine, either find another rigger because you don't trust his/her judgement, or go with it. Disclosure: I know diddly about the structural integrity of Stainless Steel at any age.
Fortunately or unfortunately, I'm not sure which, there is a mindset in this as well as many other industries to cover one's ass. So there will nearly always be a tendency on the part of a manufacturer or vendor, and the installer to include a big safety margin.
When I meet the customer face to face, I have to make sure that they understand that I'm speaking at one moment as a businessman, one moment as a fellow sailor, and one moment as a potential long term friend. One never knows. So I try to cover all the bases.
On paper, if a rig is 15 plus years. I'm going to recommend a re-rig. I often do inspections for owners who are trying to get insurance. I can't afford not to be over cautious.
As a fellow sailor, I understand the concept of a cruising kitty and limited budget, so I give my opinion on just how long and under what conditions they might be able to get more life out of it.
I try to be completely honest with people while emphasizing the peace of mind factor.
Of course, the fact that I have to make a living influences my opinions, but I try to be honest about that as well.
I never try to sell someone something that I don't honestly think that they want or need.
It does seem though, that rigging is low on the priority list for many.
I saw one guy spend over ten grand on radios, chart plotters and all kinds of stuff and completely disregard the cracked swages that my inspection revealed. They sailed off to the Caribbean.
But by and large most of my customers tell me that they "just want it done right".
I can only try to do my best for my customers based on my experience, the information I get from others and my conscience. I feel that most businesses are run by people like that too.