[notaspecialist]

When a user comes over and says "this isn't happening" I write a test and sure enough, the test fails. I fix the case, re-run all the tests, push to UAT, and ask the user to verify it works in the UAT system. It's pushed into production after hours.

Prior to TDD I would spend hours stepping through code, setting variables to replicate the scenario, scratching my head, and usually fix it after a week or so. Then I would get a bug report of something else weird happening. And repeat that process.

[vitus]

This is great, if your user report has enough details for you to replicate the problem in a test case.

More often than not, I spend a fair amount of time looking for error logs, tracing through the code, and generally getting a good sense of the exact parameters of the underlying issue.

But yes, if you identify a defect that you can replicate, write a test for it so you can confirm that a) your fix actually works and b) you don't backslide in the future.