Does using a single portrait monitor improve productivity across the board?

I have a Mac mini that I use with a single 24" monitor in landscape mode. My monitor is old, so it cannot be rotated 90 degrees into portrait mode. I feel that a landscape monitor wastes screen real estate on websites. I also read and write a lot of code and could benefit from being able to see more code without scrolling. However, splitting the code window side-by-side might be a hassle. I am determined to use only one monitor for everything. Do people who regularly use this portrait encounter any issues that wouldn't exist in landscape? Is it worth it?