When you are creating an event, if you tick the Alarm checkbox in the Details screen, a number of minutes is automatically filled in for you (5 by default). To change this default, go to the Alarms tab in Preferences, and tick the "Alarm preset" checkbox. Change the number that appears to the right of the checkbox and/or change the time unit in the pull-down menu. If you do not want an alarm to be set on every event, then untick the box; the number you have just set will be remembered and will be used as the default whenever you tick the alarm box in the event Details dialog.
This page has not yet been updated for Datebk6 - add information about the NoAlarms tag, scheduled views to change alarm settings automatically, and the Alarm Manager's ability to silence alarms.
Here is one way to turn off alarms of repeating events while on vacation:
If you usually have alarmed repeating events in several categories (e.g., Home and Work), you might want to create sleep categories for each normal category (Sleep_Home and Sleep_Work). This will make it easier to put the events back into their normal categories when your vacation is over.
If you use the Sleep category often, you might want to create a saved view called Sleep which shows only the Sleep category (with all other categories hidden). This will make it easier to re-categorise the repeats after your holiday.
Changing the categories for several events at once might be easily done in the List View, if you can use the "Opt." settings to show only the events to be changed. The List View has a "Set Category on all" menu item.