Have You Ever Asked: “What Bonehead Designed This?”
OK, be honest. It’s rude, but really . . . How many times have you asked this, or a similar question? Did you find a customer use case that the designers didn’t think about?
We run into these situations once in a while too. Hopefully, because I am a product design engineer, I give the benefit of the doubt more often than not. That said, after dealing with a ridiculous issue recently, I am back to the same question. Yes, it’s frustrating, though, at the same time, it’s a poignant reminder that I (we) must think carefully about every customer use case.
What is a Customer Use Case?
For the moment, let’s focus on customer products. All products have customers of some type, but many of those have very specific uses, so there is not as much to considering use cases.
In a nutshell, a “Use Case” is defined by one way a product will be used. Let’s use a pencil for example. The primary use case is to write. Some other ways a customer may use a pencil are drawing, tapping or drumming, as a stick, twirling, magic tricks, missiles, etc.. All of these are use cases for the lowly pencil, though not so many follow the intent. Arguably, some are misuses.
A slightly more complicated example is the license plate frames we design. Though some do end up as picture frames or other things, most are on cars as decoration of the license plate. It sounds easy enough to discuss the customer use case of simply setting the frame over a license plate, but did you know that almost every state has a little different license plate configuration? Also, every car has a different area and spacing for the license plate. Usually, that’s also different front to back. That means there are a lot of different use cases just for the basic job of decorating a license plate!
I’m happy to say that Cruiser, as a frame manufacturer, takes this very seriously. They work hard on compatibility and study because it’s a big deal for their customers. Though every frame may not fit every application, it’s pretty close. That’s a design process that helps a lot for them.
When Someone Misses
Going back to the beginning of this page, what happens when a designer or engineer misses an important customer use case? Perhaps they didn’t consider the aspects of the “Triangle of Achievable Engineering“, or, as is often the case, they didn’t employ the balancing principles of total design.
Another big mistake we see a lot is assuming a customer wants the product only in the configuration the company likes it. Perhaps certain trends are popular, so they configure the product only for those use cases. What if a block of customers don’t like that? There are some less popular opinions about product use that manufacturers choose to ignore — and by doing so, alienate customers. Or, get less than stellar reviews from the customer who has a different use case. Bicycles are an industry I know well, so I’ll give you a few examples in this review of the Pivot Trail 429.
There are many reasons, but for our discussion, let’s look beyond the miss-use. (It’s absurd to design for every possible way a to abuse a product). Let’s focus on product intent.
My Recent Example
We purchased a dishwasher, and I set out to install it. I’ve done it before, so no big deal. But . . . . Our kitchen places the dishwasher in the peninsula from the sink. When standing at the sink rinsing dishes, it’s to the side and perpendicular. This placement works well for the flow of the kitchen, but requires longer water lines for both input and discharge because they go around, and behind the corner cupboard.
The input line is a normal compression fitting. Easy. Done.
The discharge, on the other hand, has unique size outlet. The dishwasher came with a discharge hose — actually a really nice over-molded one — but it’s not long enough, not even close. Also, it’s unique on both ends. Hummm.
Turns out they don’t have a long enough hose with the right ends, and they don’t make an adapter. The discharge port is too big for a 1″ line and too small for a 1.25″ adapter. Is it crazy? What am I missing?
After several visits to appliance stores, repair shops, plumbing supply warehouses, hardware stores, etc. — after questions and photos and explanations — after a lot of head scratching by several plumbers, there is no solution. Well, no off-the shelf solution anyway. It stumped everyone.
So, we’re right back to the original question: “Who is the bonehead that designed this?”
And, Who is the manager that let it slide?
The Missing Customer Use Case

The use case is simple . . . What if the customer wants the dishwasher a little further away than standard? I just kept wondering why they didn’t make the discharge outlet a standard size so a common adapter would work? There are tons of adapters out there, so non-standard adaptations are obviously a concern. If the customer can’t use the given hose (for whatever reason), how do they connect it?
As it turns out, there is not an available easy solution. I had to make something special, then cobble it together. Interestingly, the first and second attempts at special connection both failed (in varying degrees).
Note: Failure of any type with water is a total failure. There are no partials.
Note: Tape does not work. Electrical tape as a filler (seems like a good idea) works for a few months only. Oh, and the acclaimed — As Seen On TV — Flex Tape? Well, it fails first wash!
The final solution was a force fit over the discharge port, then a modification of the cobbled adapter shown. Humph.
As One Engineer To Another
Dear engineer, please think about the customer when designing things. To me, even after thinking about this example for awhile, I just keep wondering how did you miss this simple customer use case?
As one Manager to another, please help your people think though the ways your product fits in the market. Things are often different than you expect, so help them with the “What if …” questions. Use tools, like design reviews, for access to great minds.
Also, as one engineer to others, use this as a reminder. You can do 1000 things right, yet it’s the one goof that makes customers upset. Don’t make your customers find the mistakes. Do the engineering thoroughly, and your customers will be happy they chose your product.
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