Samuel R. Delany’s technique for determining whether a phrase is redundant (if you have any question): choose one of the words you suspect of being redundant. Switch it to its antonym. If the resulting construction is inherently ridiculous, an oxymoron, you have redundancy. For example, a “large giant.” As opposed to a small giant? Other common speech-habit redundancies include the rich heiress and the consensus of opinion.
Hyperbole is a fine and respected literary tradition, and speech habits are indispensable for creating characters. (Think of Stephen Maturin’s charming habit of saying “little small.”)
But when you use these techniques, be sure you know you’re doing it — and why.