Lightroom has this wonderful concept of the virtual copy. A virtual copy is just a set of adjustments that is stored in the catalog, it's not an actual file. The beauty of the virtual copies is that it's possible to have hundreds of virtual copies of the same photo but with different adjustments, crops, colors, black and white…
Some people are amazing, years later, they remember every single detail of why they did… and then, there's me. I need to see some notes, then I can remember the tiny details. That's why I need to keep track of why I created the virtual copy.

Lightroom: Renaming A Virtual Copy to Remember the Why of a Virtual Copy