When writing or speaking, it's important to avoid repetitive phrasing, even when using terms like "that's relevant." To add variety and depth to your vocabulary, consider using synonyms such as "pertinent," "applicable," "admissible," "significant," "germane," "connected," "related," "meaningful," "valid," "important," "appropriate," "suitable," "useful," and "apposite." Using these interchangeable terms will give your language more nuance, variety, and expressive power and help you communicate your ideas concisely and clearly while avoiding monotony and repetition. So, the next time you're composing an email, essay, or speech, swap out "that's relevant" with any of these synonyms, and watch your writing and speaking blossom!