You can easily set and view due dates in Dart, both on dartboards and individual tasks.

To see due dates in your board or list dartboard layouts, click on the top right dropdown menu at the top of your screen, click on the add button "+" under properties, and choose due date. Note that in calendar and roadmap layouts, dates will always be shown.

Once you have set date visibility as a default on your layout, not only will you be able to see existing due dates, you'll also be able to hover over the task in the due date column and have the option of adding/changing them.

To show due dates by default in any new dartboard you create, go to:

Settings > Properties > Due date

Then click the toggle next to "Show".

From here you can also choose between showing a singular due date or a date range that includes both a start and end date. Just click on the toggle next to "Date range". Enabling this will also change the name of the property from "Due date" to "Dates".

There is another toggle below this allowing you to choose if you want to display the length of the date range next to the actual date range.

By default, whenever a task has subtasks it will take the latest due date or end date in a date range across its subtasks. One benefit of this is that you won't end up with a situation where a subtask is due after a parent task is.

To disable this feature, simply click the toggle next to "Roll up from subtasks" in the Property settings menu for Due date/Dates.

A due date or date range, once visible, will show up in your task under your task title:

When viewing your task, you can always change your due date or date range by clicking on the property. You can also use the keyboard shortcut R to change a due date, which can be seen by hovering over it. (If you are using a date range then alt/⌥ + R will change the start date while R will change the end date.)