Most adults sleep best with 7–9 hours a night, while those over 65 usually do well with 7–8 hours of sleep.

Most people do well starting sledgehammer workouts with 6–10 pounds, then moving up as strength and technique improve.

An average male deadlift target ranges from about bodyweight for beginners to around twice bodyweight for well-trained lifters.

Most infants sleep 12–16 hours in 24 hours, with night sleep and naps shifting quickly through the first year.

Most infants eat on demand, but broad age-based ranges help you judge whether infant feeding amounts look typical.

Most healthy teenagers should aim for 60 minutes of moderate to vigorous activity each day, adding up to around seven hours of exercise per week.

Most teenagers do well with about 6 to 8 cups of plain water a day, with more on hot days or during heavy activity.

A healthy 6’5 man usually weighs about 155–210 pounds, but muscle, fat, and health history can move the right target up or down.

A 6’4 man is often healthiest between about 185 and 235 pounds, but the best weight depends on muscle, fat, and overall health.