Every healthy individual can donate blood. The criteria to select donor is different in every country. Contact the nearest blood service to know the criteria for your country. Generally, individuals aged 17 to 65 years can donate blood. They must not have any infection which can transmit to the recipient through their blood. Healthy individuals can become regular donors and donate blood at least twice a year.

If you are a healthy human being, you can donate blood every 3 months because an RBCs life span is 120 days. So whether you donate or not, they still need to die (senescence). But they shall be replaced with a new RBC