Yes, I do agree that it's expected. But I also bet that very few non-IT people have the slightly idea on what it requires. So, let's say after 6 months that any

Yes, I do agree that it's expected. But I also bet that very few non-IT people have the slightly idea on what it requires. So, let's say after 6 months that any contract ended, they'll need some update. They'll go to the market and ask how much it costs for someone to include a new functionality. They'll get $100, $90... and your bid. You know you have all those tests and documentations properly done, then you can charge just $10 and win. And you can charge $70 and also win. It's up to you, because you know how hard/easy it'll be. And if the software was made by someone else, who charged less in the beginning? You don't know how worky it'll be, so you have to charge a bit higher, like that $90. So, from the client perspective, the difference from a well tested software and a barely-works one is just the initial price. After all contracts are over, they (remember, non-IT) can't know if the new functionality has a fair price or not. And who didn't developed it can't be sure about the maintainability, either. Having tests (and everything else) was good for you, for your future. But, in general, the client didn't knew all this. He just paid for the software...