As I lay sick on the sofa a few weeks ago I came across YouTube videos on how to use the frequency separation tool in Photoshop.
Although FS is most often used in portrait & fashion retouching (remove blemished in skin whilst maintaining structure) I did find some videos that identify it's benefits in landscape photography.
Basically FS separates the color content and the detail/structure of an image on separate layers so you can work on each without affecting the other. This can work well on images where distractions/blemishes cannot be adequately removed by other means (like spot healing brush, cloning or content-aware fills).
The following image is one where I experimented with FS to remove a distraction that really destroyed the image. I don't believe anything near this could have been achieved otherwise.
Just something to be aware of - it could save some of those 'almost' images that you may bin otherwise.
I'd be interested to hear how/if others are using FS and where they are seeing the greatest benefits.
It's certainly surprising how much FS changes the image (if it accounts for most of the difference in the two), Alan - but I like 'em both! Probably the bottom one more, though.