You can, and should, write requirements and in more general all kind of specifications / high level pictures / architecture diagrams, for when you won't be arou

You can, and should, write requirements and in more general all kind of specifications / high level pictures / architecture diagrams, for when you won't be around anymore, or even just for your future self. Maybe even more for your future self than for when you won't be around anymore, given that will impact you if you don't even if you are selfish, whereas you could just quit and not care anymore about remaining or new people. Of course you should not be selfish, but even if you are, write requirements.