Another check to run is to slowly drag your large screen window width narrower, watching for any elements running together, overlapping, line feeding, or otherwise looking awful. The width where this starts to happen is a likely breakpoint your theme needs. Keep in mind there may be no device using this width and may be too narrow for any reasonable desktop window width, so it may not be necessary to correct the display at this particular width.
OTOH, we can never know for sure what width something will be. It’s all the better if your design works at any width no matter how unlikely it is.
You also don’t want to have 20 different break points. If this seems necessary, you’re doing something else wrong. Usually, if you use percentages and vw units to size elements, you shouldn’t need many breakpoints.
