When to Start Sleep Training

Signs Your Baby Is Ready

• At least 4 months old (adjusted age if born premature).
• Medically healthy and gaining weight well, confirmed by your pediatrician.
• No active illness, ear infection, or other medical concern.
• Not in the middle of a developmental leap or regression (though waiting for the "perfect" time means you may never start).
• Showing the ability to self-soothe in small ways: sucking fingers, turning head, settling briefly when put down.

Ideal Age Windows

• 4-6 months: Best window for gentle methods (Chair, Fading, PUPD). Babies are developmentally ready but not yet mobile enough to stand in the crib or have strong object permanence.
• 6-8 months: The most popular time to sleep train with any method. Babies can go longer between feeds and respond well to structured approaches like Ferber.
• 9-12 months: Still effective, but separation anxiety and mobility (standing, pulling up) can add complexity. Be prepared to lay your baby down repeatedly during training.
• 12-18 months: Toddler resistance begins, but sleep training absolutely still works. May need slight adaptations for toddlers who can stand and vocalize.
• 18-24 months: More challenging due to FOMO, verbal skills, and potential crib-climbing. Often benefits from a behavioral/reward approach alongside a method.

When to Wait

• Active illness (cold, ear infection, fever). Wait until fully recovered, then give 2-3 days of normal before starting.
• Within 2 weeks of major travel or time zone changes.
• During a major life transition: new sibling arrival, moving house, starting daycare.
• If either parent is not on board. Both caregivers must be committed to consistency.
• Immediately after vaccinations that may cause fussiness (wait 2-3 days).

The "Too Early" Risk

Starting sleep training before 4 months is not recommended. Before this age, babies' sleep architecture is still immature, they may have legitimate nighttime feeding needs, and their nervous systems are not yet developed enough for self-soothing. Attempting structured sleep training too early can lead to excessive crying with no benefit, and may need to be repeated once the baby is developmentally ready.