The increasing expectations to image quality for stock photographers only highlights the importance for photographers to make sure their camera equipment is well maintained.
If you’re a photographer that often changes lenses, regular sensor cleaning should be part of your routine. If your sensor is dirty, your photos will get rejected because the image isn’t clear.
Using a UV filter will not only increase image quality by removing blue cast from images taken in very bright sunny conditions, but more importantly protect the acid coating on your lens. Smudges and scratches on your lens will effect image quality. A UV filter can protect your lens and easily be replaced for a far lower amount that replacing a damaged lens.
It’s fine to correct flaws in post processing, but be sure to always inspect your image at 100% before submitting.