If it's going to be relevant to the story, it needs to be there. A character who has been in several knife-fights might very well have knife scars, and this may affect how people react to them.
If it's not going to be relevant to the story, it's just clogging things up to include it.
As a general rule, the normal doesn't need to be described. "He was average height, average build, with no distinguishing features, and an unremarkable gait and ordinary clothing. Normal length hair of a kind of normal brownish." That tells us nothing; in More Tales from Section D (undergoing redrafting), there's a lengthy section on how people whose job involves remembering and describing people go through a procedure to do so, but that's a rather special case.
Minor characters don't need a great deal of description. For example, if your Point of View character is walking past a ship-yard, and sees a worker, if you then go into a lengthy description of that worker ("He was tall, wearing dirty blue coveralls with a red flash on the right arm indicating he was a senior worker. He yanked off his hard hat, and swept grubby hands through his thinning hair, a flash of gold on the ring finger of his left hand. He tossed his riveting gun to one side, and swore in a thick Geordie accent"), and we then never meet that character again, the reader is going to be confused, and the story is derailed.
Of course, that enables you to mislead the readers. If your secret Top Villain is hiding in plain sight, you can give the appearance of their being a minor but recurring character. Constantly refer to the old gardener, so that the reader never forgets them, but don't elaborate until you want the reveal.
Concentrate on what the reader needs to know. For example, in Bring Me My Bow, it's an important part of Emily's character that she's not conventionally pretty. It's important to her, and it's important to how people around her react to her. Her solidity (a consequence of being a nurse, which involves a lot of heavy lifting) is relevant. It was relevant, for reasons that are apparent to those who have read the book, to give a fuller description of Windy than for most people. It was not relevant to give a full description of Peter.
State the obvious. Your reader can't read your mind, only your words. If the character only has one arm, that's something that the POV character would notice, and it's likely to be relevant. But unless you tell the reader this character only has one arm, they're not going to know.