Event Type: Reminders

There are different types of events and they all serve a purpose. The most underutilized event type is the reminder. Let's say you have an opportunity (aka estimate) that you've sent out and you want to have a calendar event show up to remind you to follow up with the customer in a few days and again in a week. You can add reminder events in the schedule section of the opportunity and assign them to yourself. This can even send you a notification if you are making use of that feature.

Keep in mind, a job can have multiple events. This goes for "Work" events too.