I'm building a run-in shed for the horses, and for the first time in my building-things life, I fully modeled it in CAD. Originally I did this so I'd have an accurate cut list for ordering lumber and metal, but it's been WAY more useful than that. Viewing just specific parts multiple angles; custom drawings of specific layouts, even using analysis tools to figure out how much concrete I need. Super cool, I'm a convert.
(This is OnShape BTW.)