You are right. We rarely need a full description of person or place. With the former, any physical description should serve the character in some way. A description of place should try and serve the themes of the story. It is always better to focus on a detail of the person or place. For example what makes the character stand out in some way. In many instances you can get away without much physical description at all, depending on the type of story you are writing and your chosen style. It’s important to allow the reader to fill in some of the gaps for themselves and engage their own imagination. The degree to which this is done is the art of the story.