Awake at 3 a.m. again? Rebuild the habit of sleep.

A 2-minute quiz works out your sleep debt and a sleep window from your own bed and wake times.

Then the 6-week plan: $9.99 for the first week, then $14.99 a month or $69 a year. Cancel in one tap.

Built on two habit steps sleep researchers have tested since the 1970s: one fixed wake time, and a bed kept for sleep.