It is very helpful for everyone to have actually discharged one of every kind of fire extinguisher at least once in their life, preferably in extinguishing a real fire in a safe area. In the modern community starting a small fire in a safe area for this practice may prove to be an insurmountable problem. An alternative is simply to have every family member discharge an extinguisher in the open air. In the case of a dry chemical extinguisher, although they can be discharged, in practice, most discard the extinguisher. The gas, labor involved in sending it to be discharged, the waiting and the service fee is compared with the time go to go Home Depot and get another.
Once a dry chemical extinguisher has been partially discharged it must be recharged or discarded.
Fortunately, the Internat has arrived and there are free videos available showing how to use every kind of extinguisher. This gives you a good idea of how far the gas cloud (from a C02 extinguisher) or the stream from a 2 1/2 gallon water extinguisher will go. Or how to use a dry chemical unit. Do a video search.
Have everyone in the family take time from watching "The Undertaker" on World Wide Wrestling and see the fire video.
Every child in a house should be taught to use an extinguisher. I cringed once when I visited a friend and his ten year old was examining the extinguisher in his garage and he yelled "don't touch that!". Children should never be afraid to use an extinguisher or feel that the discharge (with reason) will cause them to be scolded.
Pressurized water 2 1/2 gallon extinguishers can be discharged for practice and theoretically easily refilled. You unscrew the top, fill with water, put back the top and perssurize with air at the service station. Sometimes. Many air pumps at the gas stations do not have enough pressure to properly charge the pump. You would think that you could just bring it to a municipal fire station. A neighbor did that and was told by the housewatch (taking time from reading his magazine) that the fire department did not recharge extinguishers, and that they would have to go to a commercial firm. All it would have taken was use of the stations compressor. All stations have one.
If this happens, try another fire station. And if you don't get cooperation from the housewatch, ask for the lieutenant.
Dry chemical extinguishers, of course, must be recharged by a commercial professional firm if you choose to do so.