What's the longest a person can go without using the bathroom without leaking if incontinent?

Varies widely. Leakage will occur if the pressure inside the bladder exceeds the resistance of the sphincter and urethra. Some unfortunate patients leak constantly, with leakage as soon as urine enters the bladder. Some can store urine without leakage until a cough, sneeze, or bladder contraction expels urine unexpectedly. A bladder diary can help determine an individual's situation and aid in treatment.