Both things are touched by every person that comes into the company or office. And as we are well aware, they can bring not only dirt but also germs that can be harmful for anyone. Therefore, they need to be cleaned in a regular basis to stop the spread of disease.
Take care of your employees and clients health, and do not forget to clean these spaces. It may seem not that important. But perhaps, it can trigger someone to feel bad, only because they touch the door knobs, and then, their face. So, always keep them clean.