If you’ve assigned tasks and scheduled meetings in Outlook calendar, you might want to set reminder as well. Outlook 2010 lets you change the reminder time as per your requirements. This post covers how to change the default reminder time.
To change the default time of reminding events, schedule, on File menu, click Options. This will open Outlook Options, now from left sidebar, select Calendar and from main window, under Calendar Options section, change the reminder time as shown below.