When do have you to indicate a change in direction?

You answered correctly. In German traffic rules, you must always use your indicator before turning into a junction or property lot, and also when you want to follow a priority road that changes direction. This is because in both cases, you are changing your direction relative to the current course of the road, and other road users need to be warned of your intentions to ensure safety. However, if you leave a priority road by continuing straight while the priority road bends away, you do not need to indicate, as you are not changing direction — you are just following the main straight path. Always remember to signal before any intended change of direction to make your movements clear to others.