I think Jitendra Vyas encourages me to write stuff here! This is again in response to his question on twitter asking:
Who and how decides which WCAG level should follow for a project? A, AA or AAA
In general, I have seen companies are required to meet at least Level AA of Web Content Accessibility Guidelines and the possible reason for this would be that check points up to Level AA are reasonable to achieve from practical development prospective. Level AAA requires much more efforts to achieve though not impossible.
It’s the product owner who should decide the level of conformance for the project keeping in mind the purpose of their target audience, purpose of the product, regulations of their particular region. Some regulations like the Europe may have much more strong rules than some of the other countries.
If product owners does not have such a knowledge, it’s the job of accessibility experts who should work with product owners and create a road map. However, at the end product owner should have an understanding of what they are doing and why they are doing it.
Although if decision to meet Level AA, it’s not a crime to meet Level AAA wherever it’s possible!