Defrag after each program installation?

Somewhere I heard or read that when you install a program or Os it gets scattered all over the hard drive instead of being put together in one place even though you did a Defrag before installing the new program. It stated that after every program installed it’s best to run Defrag before installing another program. Even on a clean hard drive the OS install is scattered all around and you should do a Defrag before installing the next program. Any truth to this?