March is Red Cross Month, a tradition dating back seven decades during which time people are encouraged to help the disaster relief group by giving blood. A one-time donation that can make a lifetime of a difference. Such donations are distributed to health facilities across the U.S. for life-saving blood transfusions. Here’s how to donate blood for Red Cross Month 2015, where to sign up and how to know if you’re eligible to give.

An estimated 4.5 million Americans would die every year if it weren’t for blood transfusions, according to the Blood Centers of the Pacific. U.S. hospitals go through about 32,000 pints of blood each day. Shortages often arise, especially during the summer and winter holidays, the center said. Health experts have estimated that if blood donors gave two to four times a year, the country would have enough blood to last the whole year.  

The tradition of Red Cross Month dates back to 1943 when U.S. President Franklin D. Roosevelt designated March a time to recognize the efforts of the national aid organization. “As a blood donor, I can save a life – and meeting children who have benefited really drives home the point,” Red Cross driver Greg Biffle said in a statement from the Red Cross. “The gift of a blood donation cannot be replaced by anything else in the world, and it means a world of difference to those in need.”

You can make a blood donation appointment directly with the Red Cross by calling 1-800-RED CROSS or by visiting the organization’s website to locate a blood drive near you. Giving requires donors to register with the organization, provide their health history during a private interview with a health professional and undergo a physical. The donation itself takes about eight to 10 minutes, according to the aid group. Donors should be in good health and weigh at least 110 pounds.

Most states require blood donors to be at least 17 years of age. Some states allow 16-year-olds to donate with parental consent. People who have tested positive for HIV or AIDS or have “acute infections” should avoid donating. For a full list of eligibility requirements, click here.

The aid group suggests eating a healthy meal before your appointment, getting a good night’s sleep the night before and drinking an extra two glasses of water before the donation. Don’t forget to bring your driver’s license or two forms of ID to the appointment.

For do-gooders who might be squeamish about having blood drawn, the humanitarian organization is also looking for volunteers to organize blood drives in their neighborhoods. “The everyday heroes are those who donate blood, volunteer, take a lifesaving class, host a blood drive or make a financial contribution to help neighbors here in Alabama and across the nation,” Alicia Anger, external communications manager of the Alabama and Central Gulf Coast Blood Services Region, told the Gadsden Times. “We thank and honor these everyday heroes who support the Red Cross.”