In this chapter, the routine application of thyroid function tests for hypothyroidism detection is evaluated, with a focus on the problems of overdiagnosis and unnecessary treatment, especially in subclinical scenarios. It critically assesses the lack of solid evidence behind common interventions, like the widespread prescription of levothyroxine without definitive clinical need. Highlighting evidence-based guidelines for hypothyroidism screening, the chapter argues against indiscriminate thyroid testing. It advocates for a thoughtful approach to thyroid disorder management, urging cautious use of TSH tests to reduce needless medical actions and improve patient outcomes.