Too many developers have an unrealistic view of the relationship between the quality of their software and the time and cost of creating it. The received wisdom is that more reliable software takes longer to write.
A mountain of good industry data, however, paints a different picture. Far from costing more, in the vast majority of cases improving the reliability of our code would actually end up costing us less.
The counterintuitive causal mechanism for this strange effect has been known for several decades. The later we discover them, the more bugs cost to fix. A bug discovered by users in production can cost 100x more to fix than if it had been caught as soon as the programmer made the error.
The difference in cost of fixing bugs at later stages in development can be so large that, by taking more care to catch them sooner, we can actually end up going faster.
This is a strategy called defect prevention, and it has been hugely successful at not only helping teams to improve the reliability of their code, but also to save time and money delivering working software. It’s a win-win.
The net result is that better software usually costs less to create.
Source: TDD, Jason Gorman, http://www.codemanship.co.uk/tdd.html