With fire extinguishers, you are generally required by most insurers to have an annual check by a "certified competent person" and to have a certificate of inspection on the extinguisher, and also for all of the pressure vessels have a current pressure test certificate, which here is every 5 years. Dry powder generally has to be at least turned over every 6 months and shaken so the powder flows freely inside, and CO2 and Halon do not need it.
Stored pressure has been outlawed for years, as the pressure vessels can corrode internally, as the valving is not airtight, and allows humid air to enter the cylinder, and this, along with the MAP powder fill, corrodes the cylinder from the inside out silently, meaning that using such a unit has a very high risk of it detonating when the internal CO2 pressurising cylinder is released into the container. Hose reels as well need the annual check for condition and flow, and are best as well NOT used as a general purpose washing hose, as this often means the hose is either damaged and broken, or the reel seals are worn and leak if used, resulting in poor water flow when used, or the hose is cut shorter than the regulation length ( here 15m for any reel) when it breaks from flexing.
Halon is still the only allowed agent in certain applications, mainly aircraft extinguishers ( hard to get a certified replacement that has the same properties, and is not corrosive to aluminium) and for manned space flight. As well the only thing used for fire bottles on aircraft engines, nothing else works there to put out burning jet fuel so fast and effectively, yet still have the same compact volume for the same fire kill ability.
Purchasing CO2 is harder yes, but I have a few CO2 units at home, as they are very useful, and one in the car as well. Have used the car one, and it was very effective at putting the fire out as well, and no damage done further to the vehicle as well, for which the owner was grateful, though he did also have a freshly broken window to go with the burnt fuel line that caught fire, I needed to open the locked door, and the CO2 extinguisher made a very useful fireman’s key. Also have dry powder in the kitchen, and as well some retired Halon units, as they are still fine and holding pressure, and are a lot easier to clean up from.
Been in a burning building as well, and yes you do have only a limited time to react to the smoke, more so than the fire, the smoke is the biggest killer.