Well, what kind of projects? And what order of magnitude big? Whether dynamic type errors become an issue depends a lot on how often all codepaths are run. If

Well, what kind of projects? And what order of magnitude big? Whether dynamic type errors become an issue depends a lot on how often all codepaths are run. If what you're running is a batch processing script, it's likely to crash out as quickly as a type-checking compiler, and then static types have no direct appeal. On the other hand, if it's a long-running server with a lot of finite state machines(maybe it's running a multiplayer game or something) it's really hard to reach type errors without an extensive manual test. This becomes a relatively bigger issue as the codebase gets bigger, again depending on the type of code. If the main way the system expands is by handling a more diverse set of data types, dynamic types allow less code to be written, but also make it harder to verify. In practice what I tend to see happening is that a glue layer appears that needs dynamic behavior, while the codepaths underneath that benefit more from static typing.