First, an issue of semantics. It is easy to mistake "editing" for "processing". "Processing" a photo refers to the use of Photoshop, LightRoom, or a similar enhancement program to change a photo, or ensure it is at its best.
"Editing" is the procedure of winnowing out those photos that don't make the grade. That winnowing, when done at its most serious, often means deleting them from your camera, your computer system, and your life. Editing can be painful indeed. But the fact is, it only hurts for a moment, and the benefits will stay with you forever.
The key benefit is that a carefully edited catalog of photos is one you know contains images that represent your work at its best. You can manage them, you can find them readily, and you don't have to constantly re-review images to verify if they're up to snuff.
My workflow looks like this:
1. Whenever possible, delete no-go images off the camera before downloading to the computer. These might be trial shots, missed shots, way out of focus shots - anything that tiny LCD shows me is never going to make the grade.
2. After each upload a quick review of images to delete out the ones I know can't work. Poor focus, bad lighting, or other non-correctible issues all mean a picture has to go.
3. A closer look to identify the best. Ideally, I like to have a vertical and a horizontal of keeper shots. I ask myself the hard questions about whether or not an image is all it can be. Sometimes a photo is almost there, but in my heart I know that too much grain, improper depth of field, a loss of definition in key areas should all be killers.
That said, I confess to having a heart for certain images. LightRoom offers ratings that include flags, and rankings of one to five stars. The best photographers sometimes decide that there's no reason to keep anything that isn't five stars. I can't quite go there.
As my own code, I give pictures that I love for personal reasons a two-star rating. These aren't images I would put in my portfolio, but I would certainly share them with friends and family.
I also have some unrated photos that I keep for other reasons. They may serve as a reminder - how will I do a better job of capturing that shot the next time? Or they may serve as an example of something that didn't quite work. And then, I don't mind admitting, there are the images that just leave me feeling uncertain. Is this good enough to keep? Could I play with it in Topaz or Photomax and turn it into something interesting?
When I have spare time, I like to go back through my catalog and look at images with a fresh eye. Time helps me grow less fond of certain ones, and opens up the eye to the possibilities of others. Like the image below. It has been on my iffy list for a while now. As you're improving your photography by hardening your heart to the reality of your images, help me do the same. Tell me what you think. Keep or toss?