When I moved from roughly 30 years of shooting primarily slides to the digital age with a G-3, I naturally framed things as best I could and learned to use the freebie version of Photoshop Lite that came with it for editing. Other than straightening things a bit, or sometimes wanting to be 'selective' about the subject, I didn't do much cropping at all.
But since moving from point and shoots to a 30D, then 60D and now 5D3, cropping became a necessity due to wearing glasses when I shoot. I'm seeing perhaps 80% of the image in the viewfinder. So, for me, cropping is a necessity. Having the megapixels of a 5D3 that the 30D didn't have allows some fairly heavy-duty cropping with little, if any, noticable IQ loss. I've even turned landscape format to portrait format pix when I discovered too much 'distraction' on the side(s) of the subject.