Why does my Catalog take so much space?

The most common reason is the Cache Documents folder on Windows / History folder on macOS, where your edits are located (the history of edits, including sky textures that were applied to the pictures, erased layers, the applied LUTs, masking, etc.). The logic is simple: the more images you adjust, the more space is taken by the Cache Documents (on Windows) / History (on macOS) folder.

These files are automatically removed when you remove the associated images from your Luminar Neo Catalog.