Let's say you have a list of items users can filter down. Then you should have an aria-live element that updates with the number of results. That way after each search, screen-reader users will know how many are there.

<div aria-live="polite">
Your search returned {{numberOfResults}} results.
</div>

But what if a user does two different searches that return the same number of results? The text in the aria-live region won't change, and screen-reader users won't get an update! They may think something broke or their search returned nothing.

The trick to avoiding this is use the search term in the aria-live region.

<div aria-live="polite">
Your search for "{{searchTerm}}" returned {{numberOfResults}} results.
</div>

Now screen-reader users will hear the number of results for new searches!

But there's still common mistakes you'll need to avoid.

But if you avoid all that, you're in the clear.