What is non-destructive editing in Photoshop and why is it so important?

Answer 1

Non-destructive editing is when you don't alter the photo on its original layer, and rather, work on a new layer, whether that's a duplicate or a clear layer, in order to be able to experiment with adjustments, before committing to it. It's important, because it will save you time in the long run, because if you make an edit that's undoable, then you will have to start all over, whereas if you work on a separate layer, you can just delete the layer and start over on the specific section of the overall photo.

Answer 2

Non-destructive editing techniques allow the work you do in Photoshop to be undone or changed at a later date. It is important to be able to work this way so you are free to experiment with lots of tools but don't have to start from scratch if you don't like some of the results.