COTS (commercial off-the-shelf) products are great. Someone else does all the research, development, design, and manufacturing; we just read the spec sheet and buy the products. What could be better? Beware, however, the curse of COTS.

Several years ago I was working on a project to build a small device that used several COTS components. The device was a basic audio recorder. Some of the COTS in use included AAA batteries and SD memory cards. Both of these parts are available at any big-box retailer and both are inexpensive.