Many people habitually sleep with the lights on, while others require complete darkness for restful sleep. A new study investigates this common difference in sleep preferences. The research aims to determine the impact of light exposure during sleep on sleep quality and overall health. Findings may offer guidance on optimal sleep environments for individuals with varying sensitivities to light. Understanding these preferences could lead to improved sleep hygiene practices. The study’s conclusions provide insights into whether sleeping with the lights on or off is more beneficial. Further details of the study’s methodology and specific results were not provided in the source text.