Many photo editing software programs let you edit non-destructively, using layers, masks, adjustment layers and editable project files. This means you can make changes to your image without mucking up the original data. If you need to tweak something later, you can usually just go back and change or remove it. Visuals Clipping explains that this approach is especially useful for really detailed editing projects because it gives you loads of flexibility when messing about with colour, exposure, composition or other visual stuff.