@jmreekes A few reasons… 1) BusyCal is the descendant of Now Up-to-Date which I not only used for years and years (going back to my first Mac) but also worked for Now Software for several years in QA so I know it inside and out. 2) It has robust sharing features which my wife and I rely heavily on (we need to see each other’s calendars and have a joint one for things that involve us both) 3) I like the look and feel better than the built in.