"I would not trust ANY old fire extinguisher that has not been serviced in years. What I mean by servicing is it being taken apart by a person licensed to do this."
Bear in mind that I specifically said that for CO2 EXTINGUISHERS. A CO2 bottle is just that, a high pressure bottle filled with gas. The valve is just a dump valve, unlike gate valves there is nothing to break down, jam, or fuse.
I'll stand by what I said in the context that I said it. FOR CO2 BOTTLES if the bottle has full weight, the laws of physics say it has full charge. And unlike powder, which can clog or lose the tiuny pressure charge, unlike foam, where chemicals may go bad or slowly react with neuter themselves, a CO2 bottle is "forever" as long as the bottle maintains pressure.
And, unlike all the "chemical" extinguishers, the valve on a CO2 bottle does not need servicing after discharge, because there is no chemical residue that may be in it to clog or degrade it.
Taking it to a licensed professional, who is basically a plumber, so he can perfrom $50 worth of maintenance
every year, is an indulgence for the rich--unless your fire codes require it. There are a lot of shysters in the "pressurized gas" business, both in SCUBA
shops and fire extinguishers service
If you understand the mechanics of the bottle...there's no trust issue. IN CONTEXT.