[einhverfr]

Well, I inherited a codebase where all comments fell into two groups:

1) Copyright notices and brief (1-2 line!) file-level descriptions at the top of each file and

2) Comments that the code needed to have in place in order to run properly... Delete the comments and things break. I am not kidding.

Oh, no documentation and no unit tests either. We started adding unit tests and found that things like number rounding failed.....

Years later we are still replacing the old code as fast as we can. The obvious things including braindead security issues, were just the absolute tip of the iceberg.

Nowadays I write my documentation first, then code, then at least some tests.