# MUST, SHOULD, and MAY for apps

<br />

UX requirements are expressed as instructions that you MUST, SHOULD, or MAY
follow. At a high level, you can understand these labels as follows:

|---|---|
| **MUST** | Required (enforced either in the API or in [Android app quality for cars](https://developer.android.com/docs/quality-guidelines/car-app-quality)) |
| **SHOULD** | Recommended |
| **MAY** | Optional |

For details, including a discussion of MUST NOT and SHOULD NOT, visit
[Meaning of Must, Should \& May](https://developers.google.com/cars/design/intro-terms#meaning_of_must_should_may).

> [!NOTE]
> **Note:** Be aware that Android app quality for cars specifies additional requirements beyond the design-related requirements discussed here. App developers are responsible for complying with all requirements: App quality for cars and those discussed here.