The way I figured out the concept of essentials, is to ask the question: ‘if this item wears out, would I try to replace it with something similar?’ For example, through 7 years of YLF mariner style striped tops in white and navy or white and black have always been a part of my closet. I have to replace about every 2 years due to wear, but I always replace with white and navy or white and black stripes. Coloured stripes (statements) come and go, and when they get worn out I don’t replace with the exact same colour, but rather a different colour combination.
I USED to always have turtleneck sweaters - black, dark blue and grey. Like the mariners, I would replace them with nearly identical sweaters once they wore out. Sometimes I had more black, of black and blue, without the grey. I might have a coloured turtleneck sweater, like mustard or wine, but I wouldn’t replace it like I would the black, blue, and grey ones. I’m currently down to one that is a blue/black mixed yarns, but I’m off the style, ATM - so it is no longer an essential for me.