Look down at your credit or debit card. See how the numbers are split into 4s? That's chunking and it's used to help you process and memorize information quicker and more efficiently. What are some common applications of chunking in design?
Phone numbers are one of the most common examples of chunking as it helps people memorize numbers easier.
A chunked number such as 1 (589) 312-8413 is much easier to read and memorize than a long, unchunked number such as 15893128413. This applies to other digit-focused elements such as credit cards.
Filtering and sorting
Imaging Amazon's filtering and sorting bar was all grouped under the label 'Filters'. No spacing, no sublabels, nothing. It would make it much more difficult for you to find the exact filter you are looking for. This would be a great place to chunk your filters into subcategories to make it easier for the user to find the filter they arelooking for.
Long text content
With long text content, chunking is not enough. You need to use headings, subheadings, labels, bullet points, different text decoration styles to support a particular chunk. Just think back to the last Reddit post you saw where there was no spacing at all, you probably skipped that post.
Chunking is crucial to creating content that users are able to process easily. Use supporting actions in your chunks where possible (for example, copying a long string of numbers like an IBAN).