Hi Ranjan,
Its depends on the project you are working, Actually , yes in Implementation we have to create the complete company code structure and other units manually in system where as in Roll out most of the units would be copied from the existing one.
But even in Implementation also if you have a similar type of requirement still you can go for the copy object. For example only one chart of accounts and and different company codes within same country with similar sort of requirement then you have to create one co code structure completely and you can go for copy object insted of doing manually creating other units. Thanks.
Regards
Inthiyaz