I made a mistake and it is costing my family dearly and I am having a very hard time coming to terms with it. The cost is relative but this decision is causing pain to a loved one, taking money from our very small bank account, stealing time from our finely tuned schedule, and soon it will be a major inconvenience. My dog was diagnosed with heart worms , a highly treatable - although it wasn't when I worked in a vet clinic 25 years ago, highly preventable mosquito transmitted parasite. I should concentrate on the highly treatable part of the equation, right? Well, I'm not. I'm fixated on the highly preventable part of the equation. I was diligently giving Johnders his chewable preventative every month for 2, almost 3 years, of his life. I stopped giving the tablets to him b/c in my analysis - limited and superficial - the risk/$$ ratio said the risk to him was really small but things changed and Johnders got infected. Now my seemingly thrifty decision has become a major