Resolution labels like 480p, 720p, and 1080p describe the number of horizontal lines of pixels in a video frame. More lines generally mean sharper detail, but the difference matters more on larger screens.
On a phone or small tablet, 480p can look perfectly acceptable, while the same file on a 55-inch television will look noticeably soft. If you are downloading for mobile viewing, choosing a lower resolution can save significant storage space without a real loss in enjoyment.
1080p remains the sweet spot for most home viewing setups, balancing clarity and file size well. Higher resolutions exist, but they demand considerably more storage and bandwidth for a benefit that is only obvious on large, high-quality displays.