Short answer: duplicate photos can save a meaningful amount of space, but the real payoff depends on how many exact repeats are actually in the library. Some people recover only a modest amount. Others discover that repeated imports, chat saves, and accidental re-downloads have been wasting far more room than expected.
This matters because people often expect duplicate cleanup to solve the whole storage problem by itself. Sometimes it does create a strong early win. Sometimes it mostly clears visual clutter and confidence, while the bigger storage weight is still sitting in similar shots or heavy videos.
When duplicate photos save the most
The library has lots of exact repeats from downloads, imports, or shared images.
The same photos were saved from chats, edits, or cloud re-downloads more than once.
The user already suspects obvious duplicate clutter rather than only burst-style similar shots.
When duplicates are not the whole answer
If the library is mostly near-duplicates, similar photos may create the bigger cleanup job.
If storage pressure is urgent, large videos may still beat duplicate photos for immediate payoff.
If screenshots and downloads are everywhere, duplicates may improve the library more than the total storage reading.
What duplicate cleanup is still good for even when the storage win is moderate
Even a moderate storage win can still be worth it because duplicate cleanup is one of the clearest low-risk photo passes. It reduces noise, improves review confidence, and makes the harder similar-photo decisions easier afterward.
If you want the feature route next, open duplicate photos. If you want the concept distinction first, continue to Duplicate vs Similar Photos.
Duplicate-photo cleanup is worth it when it removes exact waste first, even if the biggest hidden problem later turns out to be similar shots or heavy videos.