No Fibs — Honest Limitations
Sleep needs vary by person and age; 7–9 hours is a common adult range, not a universal rule. The "sleep debt" concept is real but debated — you can't fully "bank" sleep, and the math here (target − average) is a rough signal, not a clinical measure. Feeling (1–5) is self-reported and subjective. If you have chronic sleep trouble, see a clinician — this isn't a diagnosis.