I am a long time Canadian Blood Services volunteer. My dad developed acute leukemia in 2016 and we embarked on a six month journey to treat him and keep him with us. Unfortunately he did pass, but this is the story and one that I tell to new donors when I work at a mobile clinic.
Dad required 4 units of blood per week to support him. Two units each time. I tell new donors that today they have donated one unit. I get them to understand that four people had to donate to support one man for one week! It's a powerful realization for new donors. Most tend to think of blood requirements for surgery, car accidents and fires. They do not realize how many ways people can require blood.