Simple UI Design Is Like Clockwork

I have a theory that the best user interfaces are those proven useful over a long period of time. User interfaces, or UIs, are most often associated with operating systems, applications, and web sites. Over the course of my career in software development, I have built quite a few UIs and I find they tend to get complicated quickly.

UIs have been around longer than computers. Cars have had a user interface (the instrument panel) for over a century. Elevators have user interfaces. The baseball scoreboard is another user interface. So is the ticker for the New York Stock Exchange, or the departure and arrival board in a train station. The best user interface, in my opinion, has been around longer than any of these. The analog watch face remains, to this day, the simplest, most efficient user interface I have ever interacted with.

Recently, I decided that I wanted a watch. I haven’t worn a watch for at least a decade. I explained my requirements to Kelly:

1. Twelve large Arabic numerals on the face.
2. White letters on a black background.
3. Date is nice-to-have, but not required.
4. Sweep second hand is nice-to-have, but not required.

I’d been eying an L. L. Bean watch that seemed to meet most of these requirements. For Christmas, Kelly found me a Timex that did the same¹.

While watch interfaces can get pretty complicated, I like this one for its simplicity.

First, it is easy to read. Because all twelve numbers show on the clock face, I don’t have to guess at the time. I also don’t have to convert Roman numerals, which I work with very infrequently, to a set of numbers that I work with every day.

Second, the watch face has a consistent user interface. Three of the four pieces of information it provides—hours, minutes, and seconds—run on the same dial.

Third, it is clutter-free. There are plenty of watches that add more information to the watch face. They give the time in multiple time zones. They have compasses. They give you military time. They inform you of high or low tides. But I don’t need this information. I just want to know what time it is, and occasionally, what the date is.

Digital watches might have more compact user interfaces, displaying the digits of the time. But the simplicity of an analog watch gives you more. Instead of seeing the time as 5:25 pm, you see it relative to all of the times on the face of the clock. You can see the distance the minute hand has to travel to get from the 5 to the 12, and intuitively get a sense of the time that must pass. Similarly, you can see the distance that the minute hand has traveled to go from the 12 to the 5, and get a relative sense for how much time has already passed. Digital watches that display just the numbers don’t provide these visual clues.

I have been wearing my watch for a few days now and I love its simplicity. When I look at the time, I am not distracted by other things like how many email messages I have waiting for me. There is also something a little thrilling in knowing that it is the same basic interface that generations before me have used to parcel out the days of our years. And whether intentional or not, the analog watch is a metaphor for time as reflected in the physics of the universe, the earth rotating on its axis, the planets running their courses around the sun. It is a user interface that has stood the test of time.

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