Potassium is the counterweight to sodium. Your body uses it to balance fluids, contract muscles, and carry nerve signals, but its most important role is steadying blood pressure, and that's where a low intake matters most: over time, not getting enough is associated with higher blood pressure.
Almost nobody gets enough. Research on global intake suggests only around 14% of people reach the recommended amount, so falling short is closer to the norm than the exception.
Adults usually aim for around 3,400 mg a day for men and 2,600 mg for women, and for most people there's no upper limit worth worrying about from food. Good sources include bananas, dates, potatoes, beans, and leafy greens.
One genuine exception: if you have kidney problems or take blood-pressure or heart medication, your body may handle potassium differently, so it's worth checking with your doctor before pushing your intake up.