My variable and function names are now longer because I found that I used to shorten them inconsistently.

Errors are tested in my unit tests. If the logic leading up to the error message is wrong, I should notice that there.

Errors in POD are an issue for manual review. I do not claim perfection, and my error rate there is higher than elsewhere. But knowing that, I know to focus more attention there and so can catch a lot of those bugs.