Needs change throughout the day
Heat, physical activity, fever, pregnancy and some medicines can affect fluid needs. There is no single amount that suits every person in every circumstance, and fluids also come from foods and other drinks.
Use practical cues
Thirst and urine colour can offer rough clues for many healthy adults, but they are not perfect measures. People with medical conditions affecting fluid balance may need specific guidance rather than general hydration rules.
Be cautious with bold claims
More water is not always better, and forcing large quantities quickly can be dangerous. Build regular opportunities to drink and follow professional advice if you have been told to limit fluids.
A thoughtful next step
Use this guide as a starting point, not a rigid rulebook. Consider your own circumstances, look for reliable sources, and seek qualified professional advice when a decision affects your health or safety.