Explainers for the things nobody taught you at school and even parents don't always know: how a cold spreads and why it lasts a week, what a painkiller actually does, when leftovers become unsafe, what the humidity meter is telling you. Each page gives the short answer, the mechanism in plain words, what to do, the exceptions, and the sources — so you understand it once and use it for years.
Antibiotics act on bacteria, not on the viruses that cause colds; a doctor is needed when the signs point to a bacterial infection or when things get worse instead of better.
A flag on a lab report is a comparison, not a diagnosis: some limits describe healthy people, others are thresholds set by guidelines. The trend and how you feel matter more than one number — and a result the lab calls critical needs a doctor at once.
A blood test is worth doing when it changes the decision, some prevention is recommended to everyone without one, and for a healthy adult a supplement taken just in case has no proven benefit for preventing heart disease or cancer.
Hearing damage is set by loudness multiplied by time, and the inner-ear cells it destroys do not grow back; if your hearing suddenly drops, see a doctor the same day rather than waiting for it to return.
Headphone damage builds up quietly with loudness and time. The popular volume rule is only a rough guide: turn on your phone's sound-dose tracking, and see a doctor the same day if your hearing suddenly drops.
Blood pressure shifts with how and where it is measured, and guidelines draw the line in different places; signs of a stroke, chest pain or severe breathlessness mean calling an ambulance, whatever the monitor shows.
The card minimum keeps you out of arrears, but a small minimum can stretch a debt over many years; find out how your bank calculates it and pay a fixed amount above it when you can.
Compound interest lets returns earn returns, on savings and on debts alike; what it delivers depends on a return nobody can guarantee, on inflation and on fees.
