The catch is that "your usual size" isn't a fixed number. Because of vanity sizing, a medium at one brand can be cut very differently from a medium at another, so a piece can be true to its own chart yet still feel off if you assume every brand starts from the same place.
That's why fit reviews say "runs small" or "runs large" — they're comparing the garment to what shoppers expect, not to the brand's own measurements. Before ordering, check the brand's size guide and read the actual bust, waist, and hip numbers rather than trusting the letter on the label.
