Understanding how frequently or often a person can donate blood?

The minimum interval between 2 whole donations is suggested to be 12 weeks (3 months). This interval allows our body to restore its iron stock and ensures all the components of blood incl. RBCs, WBCs and platelets are fully replenished.
Platelet (aphaeresis) donors may donate more frequently than - as often as once every two weeks and up to 24 times per year. This is because the body replenishes platelets and plasma more quickly than red cells. Platelets will return to normal levels.
Women also need to keep in mind their menstruation cycle which is a period of blood loss and need to avoid blood donation during this period.
It is adviced to consult your physician/doctor for blood donations.