38% of bugs at Airbnb could have been prevented by using types
I think there&#x27;s a bigger issue with the narrative here. Sure, types (and tests) help avoiding bugs, and they are definitely useful in large projects like Airbnb. However, they also add a cost that is always ignored, and it&#x27;s even taboo to talk about it. You don&#x27;t want to be labeled as an &quot;anti-good-practice&quot; person.<p>But for some cases, this cost is tremendously important IMHO:<p>- Startups: being X% faster at launching your product might mean the difference between life or death for the company. This includes Airbnb back in the day!<p>- Early libraries: not being forced to use a specific type makes it easier to change your mind midway and experiment. Later when the library API is more stable, sure, feel free to add types. Thinking too structured is dangerous when trying to innovate.<p>- Personal projects: where it just doesn&#x27;t matter if it breaks in some situations and having to build a whole babel tower might discourage you from getting started for fun.<p>As an example, doing &quot;horrible&quot; things I could launch a fullstack prototype in a couple of days, or a decently working prototype in a week. Granted, I would not want to work with that code after 1 month and there would be some bugs, but the ability to get something quick-and-dirty is also very important and something categorically ignored. As an added benefit, this also allows you to iterate quickly, and throw whole pieces of code altogether because you avoid the &quot;sunk cost fallacy&quot; both from yourself and 3rd parties.<p>Please use types, and tests, and other good practices in principle. But also learn <i>when</i> it&#x27;s good to break those! I get the chills when I think on someone who blindly believes on only using X for everything and anything.