It's got to be the going, not the getting there that's good.
While the 70-431 exam covers a wide range of topics, many of the questions center on surface-type subjects. In other words, they require you to know the basics of a topic instead of in-depth details. There are exceptions of course, but this is generally the case.
One of the biggest exceptions for a database developer may be mastering some of the database administrator tasks, such as high availability, backups, security, and some of the tools. Knowing this, you can adjust your study time appropriately and spend more time on Chapters ...