Festina Lente wrote:
You can also save all your past edits as a named virtual image, and then start over with another concept. The number of virtual images is unlimited and they do not take up any disk space (well, just a few bytes in a 1K file).
This is one of the best features about Lightroom. You can go back any number of editing / adjustment steps, start over, etc. and never lose anything or ever modify your original image.