You see, critics of the pest control industry are right about one thing: they’re in it for the money. But their business model isn’t “conceal the fact that cinnamon works as a mild insect repellant so that we can sell more bug spray.” Their business model depends on developing and selling products that work as directed, and marketing them effectively. They know that some common substances like boric acid are effective—but instead of ceding the market to the laundry detergent folks, they have formulated products that contain boric acid, but that are more user friendly (contain anti-caking agents, or are combined with food-based baits, etc).
If you want to see if a pest control product distributor is serious about selling effective merchandise, look for ultrasonic repelling devices. These are popular plug-in devices that make a sound that humans can’t hear that other animals can. They don’t repel pests. This has been proven scientifically. If the distributor is selling these then they care more about making money than solving pest issues. Or you could check to see if they sell diatomaceous earth—this is an all-natural mineral substance that (when used properly) effectively kills insects and some other arthropods. It’s relatively safe to use around humans and other vertebrates, and is inexpensive. If the distributor refuses to carry DE products, then they likewise care more about the bottom line than serving their customers.
Of course prevention is always the most effective method of combating pests: if your house is clean and tidy, if all of your doors have doorsweeps and your windows have intact screens, if there are no holes in the walls or gaps at the bottom of the garage doors or cellar bulkheads, if you have properly landscaped your yard to keep it sunny and dry, if you have trash cans and recycle bins that are designed properly and removed and cleaned regularly, then you will have very little reason to spend money on either dangerous poisons that threaten your children and pets, or to misuse dryer sheets and mothballs in a misguided attempt to scare away mice, ants, and evil spirits.