If you haven't discovered the snapshot feature in Adobe Photoshop and Lightroom yet, it can be a lifesaver and is so easy to use.
Photoshop's snapshots feature is located in the history panel. Clicking on the camera icon will take a snapshot of where you are in the processing. This snapshot will include everything you've done to the photo thus far. Double click on the new snapshot image and you can name it whatever you like. The number of snapshots you can take is unlimited. Continue with your editing and if you don't like what you've done, simply click on any of your snapshots and it will take you back to that exact moment of editing, showing you all the layers and masks you had in place at the time you took the snapshot. Be aware, however, that once you close the photo, the snapshots disappear. They will not reappear when you reopen the photo in Photoshop.
Adobe Lightroom's snapshot feature can be found in the Develop module. It is located on the left between Presets and History. This is where you can save various versions and crops of your photos. Click on the plus sign (+) for Snapshots and a New Snapshot box will come up allowing you to name that version of the photo. Like the black and white photo you've created? Take a Snapshot. Then if you later decide you like it as color you can change it, but will always have that snapshot of the black and white version. Trying to decide which crop you like best? Save each crop as a snapshot and cycle through them to see which one you like the best. Or keep them all. Unlike Photoshop, Lightroom snapshots are saved in your Lightroom catalog and attached to that photo until you delete them. They will not disappear when you close the program.
If you're using Darktable or Rawtherapee, both also have the snapshot features which will work much the same way as it does in Lightroom. Snapshots is a feature you'll use over and over.