understanding source command and in tutorials

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I have done all the beginner level tutorials of ROS successfully ,and I have some questions about the source command . Please tell me if I am wrong in my sentences.

1. After each time I create the catkin workspace: source ~/catkin_ws/devel/setup.bash . But as I want to do this every time, then I did echo "source ~/catkin_ws/devel/setup.bash" >> ~/.bashrc
2. After each time I create a catkin package following the tutorial: source /opt/ros/indigo/setup.bash. This is not necesary to do with >> ~/.bashrc
3. After each time I do catkin_make: source ./devel/setup.bash

Am I wrong? Are there other cases for doing source? Is neccessary to do these every time? Thanks in advance.