Coming from a different language group I have a really hard time using German compound verbs that describe motion. Whenever I want to express a notion that somebody is moving to a new location, I think about a basic verb, i.e. "gehen", "springen", "klettern" and the destination. As a result I come up with a sentence like:
Er geht auf den Berg.
Then, however, I look the sentence up and discover that the verb is missing the prefix "rauf", resulting in:
Er geht auf den Berg rauf.
I find it very unintuitive as I already know the direction (auf den Berg) so I regularly keep forgetting about the prefix at the end. Some other examples might include sentences like:
Er geht in den Keller runter.
Er klettert über den Zaun drüber (edited).
Er geht aus dem Haus raus.
The thought process responsible for my mistake results from thew fact that I feel that I already expressed the idea of going "into" or "onto", so expressing the direction one more time feels tautological.
Is it really necessary to include those prefixes in each of the aformentioned sentences and if I don't do it, would it sound really bad for native German speakers?