Timing or amount
"normal" periods occur every 28-30 days and last 3-5 days with "modest' bleeding.
Periods are abnormal if they occur more frequently, infrequently (such as every 2-4 months), are excessively heavy. If periods require more than one pad or tampon per hour, or lead to fatigue or anemia
, this is excessive bleeding
. Periods 6 days or more are irregular.