HDR is most useful when the scene’s dynamic range exceeds what your camera can capture cleanly in a single RAW exposure.

A single RAW file often gives plenty of room to recover highlights and open shadows, but there are limits. If you have to push the shadows hard, noise can become obvious, and image quality may suffer. In those cases, a separate brighter exposure will usually give cleaner shadow detail than aggressively lifting one RAW file.

So HDR is a better choice when:

• one exposure can’t hold both highlights and shadows
• shadow recovery from a single RAW gets too noisy
• you want the best possible detail across very bright and dark areas

Typical examples include high-contrast landscapes and night cityscapes.

That said, HDR is not always the right aesthetic choice. Some photographers prefer the more natural look of a single exposure, especially in scenes shot toward the sun, where preserving every bit of detail can look unnatural.

In short: use a single RAW when it captures the scene well enough; use HDR when it doesn’t, or when recovering one RAW would compromise image quality.