Planned dates allow you to earmark tasks for a given date and time without having to assign arbitrary defer or due dates.
You can use a defer date to specify when something becomes available and a due date if there’s a consequence to not completing something by a specific date and time.
OmniFocus 4.7 introduced the planned date field, which allows you to specify when you plan to work on something. You can even specify the time you plan to do something, allowing you to, for example, earmark activities for the evening and exclude them from your active tasks list during the day.
Our Custom Perspectives for OmniFocus directory contains custom perspectives that make productive use of the planned date field. If you’re on a Mac, you can add them to your OmniFocus setup by downloading the perspective and double-clicking on the downloaded file.