Nap times go awry when we miss our “sleep window” — that magic snippet of time in which baby is primed for "la la land" and will drift off peacefully (in the right environment). Perhaps you’ve seen your baby’s sleep window open — a glazed look, a yawn, or some agitated movements (depending on age) — but by the time you finished that bite of food, changed the diaper, and swaddled, that window had slammed shut on you! One missed window can set in motion a vicious cycle of overtiredness, short naps