I recently gave a lightning talk at WordPress DC on Quick Wins for Accessible WordPress Themes. Yuri Victor, Director of User Experience at the Washington Post, stood in the back of the room and asked a handful of excellent questions of speakers. His question for me? To paraphrase:
Most of us struggle to create great experiences for 90 percent of our users. Why should we care about this 10 percent that’s in the minority?
My answer (again, paraphrasing):
When you make good decisions about accessibility, they cascade down to all of your users, not just those with disabilities. An example would be when you use relative font sizes, it allows users with vision problems to easily adjust the font size of a site. Those relative font sizes also come in handy when resizing fonts for a site that is responsive so it can better adjust to different screen sizes.
You can learn more about accessibility at WebAIM, The Accessibility Project or Accessibility Buzz.