When is a person considered to be in a state of perpetual ritual impurity? And is that by his ablution being nullified once, twice, or three times?

"A continuous 'hadath' (state of impurity) is one that does not cease, such as constant urination or continuous flatulence. The person experiencing it must perform ablution (wudu') for every prayer. It is the uncontrolled emission of something from the body. However, if control is present, it is not considered a continuous hadath, and one is obliged to repeat ablution and wash away the impurity. If the hadath is continuous, the person should perform ablution when the time for prayer begins, then pray the obligatory (fard) and supererogatory (nafl) prayers as long as the time lasts. What exits from him does not harm him, because it is a state of necessity."