Working with ATC During Development 
Use Case
(1) The developer runs ATC checks frequently during development to find and immediately clean up defects in smaller development object units, like in a single ABAP class or ABAP program, for example.
(2) The developer runs ATC checks up until the implementation of a certain functionality is complete and the ATC result is then used to clean up the code in bigger develepment object units, like a package or transport request.
Activities Relevant for Developers