When working on a project with many developers it's highly recommended to have everything strongly typed. If things are loosely typed, a small change can break the entire application. If it's strongly typed a compile time error will be given unless it's a bug due to incorrect logic.
Some people would say that this is why we have tests. Well, few have 100% code coverage on both their unit tests and integration tests. So unless you are one of those, the key to fewer bugs is to use strong typing.