Use delegation for many similar items (lists, tables), dynamically added elements, and when memory is a concern. Use individual listeners for few items (< 10), items with different handlers, and when the parent has many non-relevant children.

Every click on the parent triggers the handler (even clicks on non-relevant areas), slightly less direct than individual listeners, and requires checking e.target on every click. For few items, individual listeners are simpler.

For more than 20-50 items, consider delegation. Each listener consumes memory. 100 individual listeners is wasteful when one delegation listener can handle all of them.