Sections show your ceiling heights. Heights from 8 to 10 feet are common. People often request heights greater than that, not fully realizing how high a 10 foot ceiling really is. A graphical silhouette can help, give your drawing scale, though these are usually not shown on construction drawings. Above 10 ft you may be required to have thicker walls which can add expense to your project and cut into your finished floor space.
Sections also show your floor assembly depth. This is generally the sum of the floor joist and the subfloor above the joist, to which your finished floor will attach. Joists in the 12” range are common, but if you want a really wide open plan you may end up needing deeper joists, which would increase the depth of your floor assembly. This is usually not visible space, but increasing this depth can affect stairs, overall building height and cost.
Sections also show detail callout markers. These are usually rectangular dashed line shapes with a bubble and a number. This alerts you to the fact that there is more information about a specific area in your project on another drawing. This is because every project will have some special conditions that require the architect to provide more detailed drawings. This detail can’t be seen at the typical scale of the section, so a blow up drawing of one small area is provided. If the mark next to the callout says 3/A501 the additional detail can be found at drawing #3 on sheet number A500.