Stefan, have a look at those two websites about the use of "hem...hem de": https://elon.io/learn-turkish/lexicon/29239/hem-...-hem-(de)-... and this one with three Duolingo sentences with "hem....hem de".
Thank you very much for your time and effort, Mariane. I see now that the standard English translation for "hem ... hem" is "both ... and". Being a native speaker of German, I assumed that the German equivalent ("sowohl ... als auch") might be translatable as something with "also" in it, but I was thinking in the wrong direction.
Is it possible to say in Turkish: "Hem çalışma hem de eğlenme lazım."? That is, without the 2. person endings on the gerunds? In English "You" could refer to a specific persom you're talking to, OR to anyone. The point I'm making is that an English statement like this, taken out of context, sounds like a general truth, valid to anyone. Is the same true of Turkish?