Don’t Use a Drop-Down Menu If You Only Have a Few Options
A drop-down menu in the user interface is designed to expand when clicked and present a range of options. This is fine for customization, where there genuinely are plenty of options.
There is, however, an overhead to operating a drop-down menu: the user needs to click to open, scroll to the correct item, and then click to select. On a mobile device, this can be even slower, as the user will be using a smaller screen.
If you only have two or three options, then don’t jump to using a drop-down straightaway. Consider whether the options could be better presented to users with a different kind of control (radio buttons—for single choices, sliders, and so on).

Figure 20.1: The anti-pattern: this should clearly be a cheese toggle, not a cheese drop-down
Sort your options into a sensible order—alphabetical or numerical—rather than random. Don’t be the app that asks users...