Constitution represents your character's health and stamina. A Constitution bonus increases a character's
hit points, so
the ability is important for all classes.
You apply your character's Constitution modifier to:
• Each roll of a Hit Die (though a penalty can never drop a result below 1-that is, a character always gains at least 1
hit point each time he or she advances in level).
If a character's Constitution score changes enough to alter his or her Constitution modifier, the character's
hit points also increase or decrease accordingly.