Whilst speaking with Dave Liddament last week, I remembered a slide I've seen in some of his previous presentations, such as Effective Code Review.
On the slide is a graph that shows the amount of time needed to fix a bug at different stages of the development lifecycle.
Fixing a bug is the quickest and simplest when writing code.
It's harder when being code reviewed or QA or client tested, more so when it's being released, and the most difficult and expensive once it's in the maintenance phase.
Once it's live in the production environment, there's additional cleanup work to do which adds to the time and cost, and potentially damages your reputation.
The sooner you can find a bug, the better.
This is where tools such as automated testing, static analysis and CI pipelines shine and make it easier for you to find and fix potential bugs sooner.