A few days ago, I came across a gadget that I haven’t used in quite some time. I turned it on to see if it still worked, and sure enough, it powered up just fine. Next, I wondered what kind of batteries it required. After removing the bottom cover, I saw a big battery and immediately knew that the device would need something unusual, like a C or D size. Though I might have one or two of those lying around, I knew that I wouldn’t be willing to buy more just to keep the gadget running.

It wasn’t always like this. In my youth, I remember using all sorts of battery sizes in toys and other electronics. You had AA, AAA, C, D, 9 volt and probably even more that I’m forgetting. But fast forward to today, and it’s quite rare for a gadget to use anything but AA batteries. You see AAA from time to time, but AA is the dominant size. And if a product requires something besides AA batteries, I’d venture to say that people are less likely to buy it. After all, who wants to keep all those different battery sizes in the drawer?

Of course, there’s another trend at work here: more and more products now include rechargeable batteries. These are usually a non-standard size, but most people don’t care, since you rarely have to worry about replacing them. But if you happen to be designing a product that still requires disposable batteries, do yourself and your customers a favor. Stick to the popular AA size and include some name-brand starter batteries in the box, and your product will sell on its merits — rather than getting rejected by potential customers because of unusual battery requirements.