A primary care clinician (family physician/internal medicine) is often the best first step, because insomnia can be linked to thyroid issues, anemia, medication effects, chronic pain, reflux, and lifestyle factors. They will assess duration (acute vs chronic), sleep schedule, caffeine/alcohol, stress, and accompanying symptoms. If there is loud snoring, witnessed breathing pauses, morning headaches, or strong daytime sleepiness, referral to a sleep clinic/pulmonology is common, and a sleep study (polysomnography or home testing) may be recommended. Prominent leg discomfort/restlessness points toward neurologic evaluation and iron status assessment. If insomnia co-occurs with anxiety/depression, psychiatry or a psychologist is valuable—especially providers who deliver CBT-I, the first-line treatment for chronic insomnia. Urgent care is warranted for suicidal thoughts, manic symptoms, psychosis-like experiences, chest pain, shortness of breath, or confusion. Evidence base: ACP CBT-I first-line guidance; Mayo Clinic overviews on sleep disorders; AASM/NHLBI diagnostic pathways for sleep apnea.