Why do they turn on the sirens every other day in Michigan?

When I lived in Michigan (Farmington Hills), the sirens were on so often, it seemed like it was several times a day. It was prettymuch always a test. They turned on the sirens so often, that when there actually was a tornado, I didn’t take cover because I was used to constantly hearing the sirens and thought it was just the norm. IMO this kinda renders the warning system useless and just an un-needed expense. Why do they constantly blare it in Michigan?