may not be useful when the code "works" for anything from 15 mins to 48 hours before crashing

My first mentor, Howard Taylor, had this to say: "anyone can make a clerical error but as you write code, you should make sure you make no functional errors".

Of course I asked "what is a clerical error, amd what is the other.

answer: a clerical error can be fixed by replacing one word/number, a functional error require recode.

In the many years I have lived by that rule, I have found that clerical errors make the program crash NOW and can be found quickly, while functional errors often result in what Jerson describe and can take days to catch.

Well, in a roundabout way I got to my mantra: "you can not rely on testing, quality can not be tested in, it can only be designed in.

So, while Jersons suggestions may be excellent, if you need them, you have not spent enough time on your coding.

Erik