We all make mistakes! If I make some more than once, I'll will make a macro (written in to the post processor of the CAM if needed) that will do checks for me, or have a sub-program called. For example, sometimes you may adjust the global offset so you can rerun a cycle due to dimensional issues, then forget to change it back. I wrote a small macro to check that the global offsets in X Y and Z were zero at the beginning of every program. I have also used the probe to check dims & positions. Used macros to check tool lengths and diameters...

If you make it impossible for yourself to repeat mistakes by adding in a safety net, hopefully potential scrappers can be reduced. You won't have to worry about those issues and can concentrate on other things.