According to Matthew Walker's research, books, and lectures, the most powerful sleep improvements don't come from supplements or gadgets, they come from a handful of consistent habits.
The single biggest lever is regularity: going to bed and waking up at the same time every day, including weekends.
Pair that with a full 7–9 hours (you cannot train yourself to need less), and you have already outperformed most people's sleep hygiene.
From there, it's about protecting your body clock: get 20–30 minutes of bright morning sunlight, dim your lights and screens in the evening, and keep your bedroom cool — around 16–19°C.
Caffeine after lunch and alcohol before bed both quietly sabotage your sleep quality in ways you may not feel until it's chronic.
Round it out with daily movement, a calming wind-down routine, and reserving your bed strictly for sleep — and you have a system that Walker himself would likely call close to optimal.
For those over 60 especially, these habits often deliver more benefit than any supplement on the market.
The book is available in several languages.