Don't flip every mattress: Tempur-Pedic has a designated sleep side
Tempur-Pedic advises against turning its mattresses upside down. Rotating head-to-foot is optional rather than required; always check your own mattress manual.
Advice to flip a mattress periodically is not universal. Tempur-Pedic says its layered, one-sided mattresses should not be flipped, as this can affect performance and warranty coverage. Rotation from head to foot is optional. These manufacturer-specific details must not be generalized to other mattresses.