Should I buy my jackets and sweaters one size larger than the size I wear for t-shirts?

Supposing that we are talking about the same brand, and I usually wear a size small for tshirts for this particular brand, should I buy my jackets and sweaters in size medium since I always wore a tank top and/or t-shirt under my jackets and sweaters? Or do companies already added to measurement, and have already enlarged their the measurements for jackets and sweaters, assuming that consumers will wear tshirts and/or tank tops under their jackets and sweaters? So should i buy a size medium or size small for a sweater (cardigan) from a brand i usually buy and fit size small t-shirts from?