RIDDEX Sonic Plus Pest Repeller

We had three of these plugged in throughout our home over the course of about a year, and we have just as many bugs and spiders in our house as we did before. Later I read that most insects don't have ears and cannot hear anything, let alone high frequency sounds. So how could this work? Waist of money! "Ultrasonic pest repellers are a hoax and have fooled many unsuspecting consumers. While they seem like a nice family- and pet-safe solution to traditional pest control methods, they are a scam; which is a bummer because the idea of them sounds great. A few studies have shown success with specific insects, such as crickets. However, this success was usually very localized. For example, the pests might have avoided the one particular room where the electronic pest repeller was located, but they did not evacuate the entire house. There has been no proven success on cockroaches, ants, spiders or rodents."