Efficient way of non-destructive editing in Photoshop

»and making adjustments per layer«

Applying Adjustments destructively to Layers seems like flat-out nonsense from the perspective of non-destructive image editing. 

»or merging each layer once it is to your liking and going to Layer > Adjustments to make any changes«

What is that supposed to mean? 

Why merge? Merge what? What about Smart Objects? 

Maybe you could post an example? 

I came to say pretty much what @D Fosse and @Trevor.Dennis have said, especialy D Fosse's bit about "reversible," which really is what we mean when we speak of this issue. There is no "non-destructive" editing. That's an oxymoron. The way to ensure you don't ruin your whole day inadvertently is:  Always keep the original unedited image as your background layer (I deactivate that layer so as not to accidentally work on it) and do not touch it in any way, or save it to your computer somewhere else, or whatever you need to do to keep it untouched. Work ONLY on duplicates of the original in case you make an irreversible error or realize it belatedly when there aren't enough backward steps left.

-edit typo

Like so many things with Photoshop, it comes down to context.  What sort of editing are you talking about?  Is it improving and making the most of a photograph? Is it compositing where you combine elements of multiple photographs?  Is it illustrating from scratch, or full on digital art?

With photographs you do have options that allow you work non destructively, with Smart Objects being one of the most powerful. You can apply any number of effects, but still get the original image back by turning them off.

You can make use of blending modes to apply 'some' effects non destructively.  The 50% grey layer set to Overly is a classic example where you can brighten or darken parts of an image without directly impacting the image, but you can also use the same trick to add noise to an image.  The background image below is completely untouched, but the 50^ grey layer above it has had noise applied, and with its blend mode set to Overlay the noise is transferred to the background image.  I used the layer mask to show a before and after.

I often do the same thing as Dag, adding a copy merged layer to the top of the stack (Shift Ctrl Alt E) and might use it as a new starting point, or might add a layer mask to the copy merged layer to use just part of it, but this is very definitely NOT non-destructive, and will lead to a build up of degenerative effects on the image.

If you gave us a more detailed account of what sort of work you are doing and what sort of edits, then we could probably give you a more meaningful answer.

I think "non-destructive" is really a misleading term - any editing is destructive. That's why we do it.

A much better term is "reversible". That gets to the core of it - you can go back and rework at any time, without any further damage. But you can't do that if the adjustment layer is merged.

My own experience is that reversible only goes so far. Image editing is a continuous unbroken flow. If I can't finish in one sitting, I often find it pretty useless to reopen old adjustment layers. I'm in a different frame of mind and can't remember how I was thinking. So I tend to merge at least most of the layers before final save. If I need to go back, I actually prefer to start from the beginning. But that's me.

Moved from Download & Install forum.