It's not just age, there are several other factors to consider. For example, I dive with Scubapro 2x MK10s & 2x G250s, and I'm pretty certain those are rather old.
- Age
- Brand/Model
- Reliability/Quality
- Technology
- Features
Now for a professional environment, it's probably easier if you can put a simple number on something like "20 years" rather than pointing out 5+ factors to consider.
I'm not familiar with Aqualung Glacias. What I will say is old Aqualung & US-Diver regulators certainly go VERY cheap on places like ebay.
In a professional environment, especially with equipment your life depends on it, yeah, they should definitely replace it, based on your description. Regulators should practically never need replacement pieces outside the normal maintenance schedule. Are they skipping the standard service schedule, or are the regs just that bad? Being delayed getting in the water to save someone's life because
"oh ****, this 20+ year old cheap regulator needs service again, grab the spare" could be the difference between saving a life and cursing at your gear.
- Talk to your coworkers. Do any of them feel the same way?
- Research: Determine what you would replace them with. Ideally, something that shouldn't need replacement for another X-years. Also ideally, not something absurdly expensive. If you come up with a few options, including listing pros and cost of each (lets say how long they're likely to last, etc ... including some which you think are too pricey for them), you might save them some time and headache doing the research themselves, or find they replaced your regs with ****** ones.
- Come up with a value proposition. This one is easy, if you have any stories like the above, where regulators are every not ready when needed, or someone's reg blew up under water. However, even stories of regulators being in disrepair and needing to be swapped in non-emergencies could be translated to "that would have sucked in an emergency."
- Professional Standards: Figuring out what other people do in the industry can help (which is what this thread is about). I unfortunately know little of this, but maybe other people can chime in.
(Somewhat off-topic warning)
Another option would be to use personal equipment, and consider that just another "cost" (as in "cost benefit analysis", not always financial cost) of your employment. I do this quite a lot in my profession as a software-engineer, often buying certain pieces of equipment because I get tired of arguing with my employer that I need a 50-inch 4k monitor, when I can just get one for about $400 on black Friday. That may seem silly, and certainly my coworkers laugh at first when I show up to a new job with a giant monitor (or two), but when I have to have 4+ projects open, plus a bunch of other stuff ... my coworkers start to see why it's not a joke & my productivity long term
makes me more competitive in the job market and more than pays for that kind of equipment.
There are limits, for example, I'd never buy a laptop for work, those are really expensive and "take it with me when I leave" factor is ruined. Same with a lot of software, since I might only need it for that employer, or there are annual licensing costs.
The additional servicing costs of personal equipment are where I'd probably put regulators in this category, of not worth it. The possibly saving your own life, is where I might lean more towards considering it.