E is dependent on the location(point), provided no changes to the charges at the source. It is independent of the test charge placed at that point. If I have a charges Q1 and Q2 at a distance r apart. At the location of Q2 the electric field E is dependent on the source charge Q1 . At the location of Q1 the electric field E is dependent on the source charge Q2. In other words at the location of a charge Q the electric field at that location cannot be due to itself.
