I (in an affluent US east coast suburb) called my fire dept's non-emergency line to ask about this once a few years ago, and they told me this isn't something they do. So who does it?
What I can give you is the next best thing: A way to self-check. Most fire extinguishers have both an expiration date and a pressure gauge. You want the pressure to be in the green and the date to be in the future. They usually last 10-12 years with proper care, but you still want to regularly check these things.
My source for this: An inspector, who checked the extinguishers for the pharmacy I worked at back then (was employed or contracted by the pharmacy chain). It has been over 10 years, but it doesn't look like this information is out of date.
In your case I'd search for a company that is certified by NICET [2].
[1] https://www.nfpa.org/news-and-research/publications-and-medi...
[2] https://www.nicet.org/certification-programs/electrical-and-...
It helps a bunch in an emergency when you are not preforming a technical operation for the very first time.
I will concede this may be tricky to pull off in a more urban environment, "Yes officer that's the idiot who lit his garbage can on fire in the middle of the street", in which case do without the fire, or make friends with the local fire department and they will let you do it in their parking lot.
There are small tests recommended each one or two years, but also a more serious test. The bottle will probably need to be tested for an integrity check each five years to see if it can hold the pressure without bursting. Owner can't do this test by the risk of blow and the lack of the machines.
Really? Do you know _anyone_ who does that? What will the professional do that we don't -- take a look at the charge level, take a look at manufacturer date?
For private people it's less common to do that.
Here in Germany, the checklist is as follows - and government as well as insurances can and do audit companies if that is being followed:
- check for accessibility: is the location of the extinguisher properly marked on maps and does the wall have visible indicators that show where the extinguisher is? Can the extinguisher be reached and grabbed in an emergency or has random clutter accumulated next to it? Are the maps and indicator designs outdated? Are the indicator signs autoflourescent to make them visible even in the case of a fire-caused electrical blackout? Are there enough maps publicly visible that everyone can access one in case of emergency?
- for wall mounts: check if the holder is structurally sound or if someone ripped out half the screws by bumping into it?
- check if the tank itself hasn't expired. A tank usually is certified for ten years.
- inspect the extinguisher visually, look for dents etc. that may have led to corrosion of the tank or damage to the hose/nozzle (and subsequently a rupture risk should it be used). That is a very common occurrence in portable extinguishers that have been used as door stops.
- check if the extinguisher has been used / the seal been broken. If yes, that demands a full replacement of consumable parts (pressurizer agent, extinguisher agent, seals).
- check if the interior of the tank has been damaged by corrosion
- check if the pressurizer agent is not expired (most extinguishers here aren't permanently pressurized, instead they contain a CO2 cartridge) and weigh the cartridge to make sure it hasn't leaked
- check all O-rings and replace if necessary
Or fire codes.
Related off-topic reminder, in the hope it may save one life one day: please use this comment as a reminder to check upon the status of your smoke alarms, carbon monoxide alarms and fire extinguisher. At the very least every room where people sleep in should have a smoke alarm and every room with a furnace (boiler, oven, kitchen, ...) a smoke and CO alarm. They must not be painted over, and their batteries be regularly replaced.
Each story of a house should have at least one extinguisher rated for classes A and B (solid and liquid combustibles), kitchens additionally a class F extinguisher (DO NOT EVER use a water/foam extinguisher on a fat fire). Fire extinguishers should be inspected by a licensed professional every two years and must not be used again after breaking the seal without a check-over by a licensed professional.
Also, have your building's electrical lines checked at least once a decade and after each major rework if they are up to code, and regularly check appliance cables for damage. Electrical defects account (in Germany) for roughly a third of all fires.