Many companies are happy with the features SharePoint provides out of the box. Usually the only customization they want to do is change the webpage layouts and design to make them go along with their corporate design. For this purpose, they have a production SharePoint farm and one for test purposes. The customizations are done with SharePoint Designer on the test farm, and after they have been tested thoroughly they are rolled out to the production farm. But, more often than not, the day comes when SharePoint Designer isn’t enough and the SharePoint developer has to take the next step up to Visual Studio.
Source : 4sysops.com
