Consider the image in which there is an exposure issue. Of course with today's high res RAW files we can correct enormous changes in exposure with controls available in post-production. But the habit of doing so and the time invested are two of the main reasons to make the correction at the time of capture. For each image you open in Photoshop to edit, you'll double or triple the time IF you have to continually make global adjustments for the exposure or color balance.