A thought for you.
Sometimes you do not have the right lens. Like, imagine you have a wide 16-35 lens:
Fine. But what if I had wanted a longer lens? I did in fact have one, but if I had not had it, I would simply crop. We sometimes forget, with all these pixels, we can crop dramatically and still be able to make a nice print. That photo above, I could crop like this:
That composition is more to my liking, and yet, it still maintains enough pixels for a print: this crop is around 2500×1800 pixels, i.e. some 4.5 megapixels: enough for an 8×10 for sure.
So next time you have a shot you wish you had had a longer lens for: Feel free to crop!