Routines as powerful sleep cues.

Studies across countries, including large international surveys published in the journal Sleep, find that children with regular bedtime routines fall asleep sooner, wake less often at night, sleep longer overall, and show better daytime behaviour. The effect is dose-dependent: the more consistently the routine is followed, the better the outcomes.

A key 2009 randomized controlled trial by Jodi Mindell and colleagues in Sleep demonstrated that instituting a consistent nightly routine for infants and toddlers significantly reduced sleep-onset latency, night wakings, and parental perceptions of sleep problems within weeks. Control groups showed no such improvements. Language-based elements such as reading or storytelling are especially helpful.

A longitudinal study by Hale and colleagues found that preschoolers who had language-based bedtime routines (reading, storytelling, or singing) at age 3 slept about 0.2 hours longer per night at age 5, even after accounting for family background factors. These routines also supported better verbal skills.