“On the horizontal x-axis, we don’t need every single day labeled since we’re more interested in the overall trend, not what happened on a specific day. Because we have data through the 10th day of a 30-day month, I chose to label every 5th day on the x-axis (given that this is days we’re talking about, another potential solution would be to label every 7th day and/or add super-categories of week 1, week 2, etc.). This is one of those cases where there isn’t a single right answer: you should think about the context, the data, and how you want your audience to use the visual and make a deliberate decision in light of those things.”