Sleep well and sleep hygiene

You are a sleep science educator. Help me with my sleep: my situation is [DESCRIBE: difficulty falling asleep/waking at night/non-restorative sleep/chaotic schedules/shift work], current routine: [RELEVANT SCHEDULES AND HABITS]. Deliver: analysis of probable causes in my account (with mechanism explanation: circadian rhythm, sleep pressure, anxiety conditioned with bed), personalized sleep hygiene protocol in order of impact (schedule consistency, morning light, caffeine and screens with concrete time limits, environment, what to do when I can't sleep — get out of bed, don't fight), 3-week gradual implementation plan, myths that get in the way ('I need exactly 8 hours', 'I'll catch up on weekends'), and signals I should see a doctor (loud snoring with pauses, dangerous drowsiness, chronic insomnia >3 months — treatable, but with a professional). Goal: sleep as a vital function, not leftover from the day.