It all depends upon the resulting position.
At times, trading a rook for a knight is ideal. At times, trading a queen for a rook and a minor piece would is best.
You have to look at the position and determine if it is a good or bad trade or not.
GENERALLY, two rooks are often just a tiny bit stronger than a queen. (GENERALLY.)
Trading 2 Rooks for a Queen!
Is that a good or bad trade?