The ribbon bar Show area check box Reminder enables or disables the display of:
If this box is checked, then appointment reminders are displayed when the occur and start-of-event-messages are displayed. If it is un-checked, they are not displayed.

The Appointment Reminders form allows you to:
At the start of an appointment you will see an alert that allows you to open the appointment:
Deal Expected Dates do not generate an alert. There is no specific start time for an Expected Date only a start date. If there is a specific time-and-date for a deal - like a bid opening or a real estate closing - then set a appointment.