> I tend to have the next obvious replacement parts on the shelf already What I was going to say, moreover when you have a tool that is critical to your job,

> I tend to have the next obvious replacement parts on the shelf already What I was going to say, moreover when you have a tool that is critical to your job, you get a second one. It doesn't have to be a great one, it can be the old one that kept failing so you decided to buy a new one, whatever but just good enough to save your life Incase your critical equipment fails.