Insurance companies. I'd love to know how they weight different variables when determining the cost of policy (applies for health, car, home etc). If I install

Insurance companies. I'd love to know how they weight different variables when determining the cost of policy (applies for health, car, home etc). If I install $100 worth of deadlocks, will that save me $5 / year or $50 / year on my policy? What other variables aren't I even thinking of improving?