Back when I started shooting color positive slides in the late 80s there was a lot of emphasis on using the viewfinder for composition, and to crop in post only when necessary. Composing with the viewfinder has made me a better photographer, and in time while framing one scene other compositions would pop into my head. Subject permitting, I can get those scenes into the camera so composing with the viewfinder is a good thing. I also wanted to keep as many pixels as possible because when I make prints, I like to print them poster size (90CMx60CM on matte canvas and gallery wrapped). Back when I was shooting with 10MP and 12MP cameras not cropping in post was beneficial for making those large prints.
But not cropping at all in post has been detrimental to my photography because no matter how much effort I put into composing with the camera sometimes I do not see a better way to frame the subject until I can view the image on a bigger screen. Plus, I like to shoot active critters and they do not seem to cooperate. So, nailing the framing with the view finder is not always possible. Also due to the way that I shoot, holding on to the critter's perch with my non camera hand, I must guess what the magnification needs to be to get the framing that I want before I move in to take a shot. Once I am in position it is difficult to back out and make changes without spooking the subject. So, if I start shooting and realize that the framing is not what I want I am better off just cropping in post. Since I am shooting with a 24MP sensor I can afford to toss out a some of the pixels without sacrificing print quality, so I decided to start cropping when it makes sense to do it.
I use Photoshop Elements 2022 for my image editing and while cropping a shot I got a nice surprise: If I set the aspect ratio to the same aspect ratio as the original image, at 300 DPI, I end up with a 24MP image even after cropping. Elements must be extrapolating out the data and, so far, it looks good. I have been cropping after color correction and sharpening, and the detail seems to be holding up. One of the benefits of being able to crop and keep the mega pixel count high is that I can shoot at lower magnifications than I normally would and get more depth of field. So, cropping an image in post is going to be good for making the most out of the limited depth in a single frame. I took this shot at about 1.5x and cropped it slightly to eliminate some dead space to the right of the subject. The composition of the original shot is fine, but making it tighter looks better to me.
I will still compose with the view finder, but I am not going to avoid the cropping tool if it will make my images look better...