Remember that each woman has a different experience. Some women have such a light period that they only notice it because they find spots in their underwear. On the other hand, a woman with endometriosis will probably start being in excruciating pain the day before the period starts and will know exactly how long it lasts.

Source: I know someone with endo. She also has a resistance to at least one OTC painkiller because she used to pop those things like candy. And a female coworker of hers (with a very light period) thinks that most women are exaggerating and that periods aren’t much of a problem…