# Frontend A11Y Aria Patterns > Use when building a UI widget that has no native HTML equivalent (tabs, combobox with custom rendering, listbox with rich options, menu/menubar, tree, treegrid, carousel, custom modal) and you need to know which ARIA roles, states, and keyboard model the W3C WAI APG mandates, when announcing dynamic updates to screen readers (status, alert, save toast), when deciding between `aria-label` and `aria-labelledby` and `aria-describedby` and `aria-errormessage` for an accessible name and description, when a screen reader is silent on a component that visibly changed, when keyboard focus or screen-reader announcement order does not match the visual order, or when a code review flags `role="..."` and you must verify whether the role is needed at all. Prevents the first-rule-of-ARIA violation (slapping a role on a div instead of using the native element), `aria-label` overriding visible text, redundant roles such as `