I have one rated for grease fires in the kitchen and one rated for Magic Computer Smoke next to the electronics.
(I live in a small apartment, so two is probably already overkill).
Also, second pro-tip from a Firefighter friend: Regularly pick up your Fire Extinguisher and flip it upside down and tap the bottom like you’re trying to get ketchup out of a glass bottle. Often the “dust” inside the extinguisher can settle for too long and when you go to use it… nothing comes out because it is all compacted on the bottom of the Extinguisher. So occasionally making sure everything is loose and ready to go is key. He suggested to me every few months to do it.