To locate a decent fire extinguisher services provider you should look for a comfortable combination of quality and price. Some frauds can set really high rates on their services and actually not do anything that is really required, and you'll learn it only when your house burns down to ashes. You don't wan this to happen to you. Thus, high charges don't necessarily mean decent fire extinguisher services.
There's the saying: "People are talking." This is exactly what you have to look for when searching for decent fire extinguisher services. When checking your list of fire protection companies in Los Angeles, ask them for feedbacks. Normal companies that have nothing to hide from their customers would easily grant you the contacts of their previous customers, and you will be able to simply contact them and ask what they think about their fire extinguisher service provider. You can immediately cross out from your list the companies that refused you in your favor. You can also ask your friend, parents, or neighbors about the services they use. They will gladly advise you on something.