Editing the scales and limits on the Dashboard components is a good news, bad news type of feature. The good news is that you can easily change these items; the bad news is that knowing which components contains scales or limits can be a bit confusing. And, once you determine which components contain scales or limits, you have to do a bit of mental math to come up with the proper values.
A scale is the interval unit used in a bar chart. For example, depending on the products you sell, you might measure your sales pipeline in intervals of hundreds, thousands, or even billions. Like its name implies a limit limits the amount of data that you see in a component. For example, by default the top 10 opportunities component limits the data to 10 items. However, you can change that limit to only include fewer items or increase the limit to include more than 10 items.