Making your site accessible to people with disabilities is just the right thing to do, and in many cases it’s a requirement.
A lot of the work we do is in higher-education, where we’re required to adhere to WCAG 2.0 Level AA standards.
During the design phase we use tools such as Stark to ensure legibility and contrast of all text, and visually simulate how the experience will look for people with color-blindness. And during development we use tools such as WAVE to assist with identifying any possible accessibility issues.
For existing projects, we can do a comprehensive accessibility audit, that results in a to-do list of issues, along with severity and recommended changes.