Never delete your raw files.
Whilst looking through my archive of images I came across these two raw files from a trip to Lake Bled last summer. At the time I vetted these images, and for good reason, as you can see the original images were not taken anywhere near correctly. In fact it is difficult to find anything right about them. However I decided to tackle these images as an extreme example of when you don't bracket and have only 1 (very poor) exposure to work with the kind of recovery is possible with raw files and some time. Why is this significant? Well if you are new to photography and finding your feet in post processing it can be easy to dismiss a raw file and think it's worthless. However as your skills develop, your workflow becomes more extensive and your knowledge of files increases the more options you have open to you.