What is the difference between Date Based action and Time Based action?

Date Based action:

If the workflow type is Date based, the criteria for the trigger would be checked only on that date after which the action will be carried out.

Time Based:

If the action to be carried out is Time based, the criteria would be checked in advance but it will be executed only at the given time.

For example, let's take that you need the system to send an email to a customer at 6pm exactly after 7 days. You can set the the workflow to execute after 7 days and use the **Time Based** action to send an email to the customer at 6pm .