This is majorly done on cloud solutions. during development you try to always have a product. you create a so called mvp (minimal viable product) and then extend it continuosly. examples are facebook, twitter and many other webapplications Write My Cheap Essay & you most likely often use. these applications change over time (new features are added, removed or changed). the idea is that you always deploy your new or refactored code, when a feature is ready, where ready means it creates value