Just to introduce myself, I'm a software developer. I've been working in agile environment for past few years, which made me notice some changes in the way people around me handle their daily tasks.
In a traditional way, you plan and schedule your tasks so that you can synchronize your activities with other actors or events. Going agile usually means relying on "best effort" concept and delaying decisions (see Lean Principle #4 – Defer Commitment), which results in a spontaneous behavior:
Are you hungry?
Yep, lets go for a lunch!
Thinking of information systems, most of them can be (actually should be) designed without time-based synchronization. Using timers is a sign of poor design unless you need to represent a real-world timing need. For example, you can hardly implement this without a time tracking device:
Wake me up at 06:00.
But this you can implement easily:
Wake me up when sun rises.
You simply poll or listen to a light sensor, no time tracking is required. Adding some queues allows you to handle any kind of day-to-day situations. Let's see some examples:
Example 1: synchronize for dinner
My workday ends at 17:30. The dinner is better ready by 18:00.
Wife: estimates the time required to cook and polls the clock to start the activity on time.
Wife calls me: Everyone here is getting hungry. Are you leaving for home yet?
Me: Yes, getting hungry, too. You can start cooking. or No, have to finish something. Dine without me.
With notifications / listeners:
Getting hungry and tired. Text my wife: Leaving. You can start cooking.
Example 2: dentist appointment
Me: Can you take me next Tuesday at 08:00?
Me: Can you take me now?
Dentist: Sure, I'll be expecting you. or No, call me later.
Notification and queue:
Me: Can you take me now or you are busy?
Dentist: Busy. I'll let you know before I take the last patient currently enqueued.
Example 3: flying away for a weekend
Me: Wife, call the airport. Tell them to fuel the plane by 09:00 on Saturday.
With a notification and queue:
Me: Kids, how about a weekend in YOUR-FAVORITE-PLACE-HERE?
Wife: I just called the airport. They will fuel the plane as soon as they can.
Me: OK, we're waking up when the sun rises and leaving for the airport after breakfast.
As these examples show, it is possible to completely avoid time-based synchronization. It was hardly imaginable 50 years ago, but it's real today. Now that have a way to notify and poll on demand (some people literally live with a phone in their hand), isn't time-based activity synchronization just an old custom?
Final thought: time tracking will still have to be used for scientific purposes. In some cases it, too, can be avoided, though. For example, performance of an engine is commonly measured in time-based units (horsepowers), but aircraft engines are compared by delivered thrust (a time-independent unit), which can be easily adopted to automotive engines, too.