MEN1 surveillance is lifelong because endocrine tumors may emerge at different ages and in different organs. Current guidance favors targeted surveillance rather than indiscriminate hormone panels. Parathyroid disease is screened biochemically beginning around age 10. Serum calcium is the initial detection test; routine PTH measurement is not recommended as the initial screening test. If calcium is elevated, PTH helps establish whether the hypercalcemia is PTH-mediated. Pituitary biochemical screening begins around age 10, and pituitary MRI begins around age 15. New headaches, visual symptoms, galactorrhea, menstrual changes, sexual dysfunction, or symptoms of hormone excess require evaluation sooner than the next scheduled study. Pancreatic surveillance imaging begins around age 15, usually with MRI every 2 to 3 years. MRI is preferred for routine duodenopancreatic neuroendocrine tumor surveillance because it avoids repeated radiation exposure. Thoracic imaging for thymic and bronchial neuroendocrine tumors begins around age 20 to 25 and is repeated every 3 to 5 years. CT is preferred for thoracic surveillance. Routine chromogranin A testing, broad gut hormone panels, and fasting glucose/insulin measurements are not recommended for routine surveillance in asymptomatic people....