Show All Options If Under 6

Match fields to the type and size of the input. Placing options in a selector drop-down requires two clicks, and hides the options. Use an input selector if there are over 5 options. Incorporate contextual search within the drop-down if there are over 25 options.

Avoid drop-downs when there are only 2 or 3 options that could be displayed as radio buttons (which require only a single click or tap).