Cover each topic in just as much detail as users need

Including a topic doesn't necessarily mean that you have covered it adequately. The goal should be to include enough detail for users to do their tasks, but no more detail than they need. While you're analyzing tasks, you might not be able to anticipate all the details of a task; later, when you're writing, questions of detail will arise.

Judgments about the completeness of detail are usually more subjective than judgments about which topics to include. For example, deciding whether to include a topic about troubleshooting is easy, but determining whether to describe error situations that rarely occur is not. Writers who “put themselves in their users' shoes” can usually make good decisions about how much detail is needed.