I’ve been donating blood since I was in high school. My dad is a long-time blood donor, so I started giving because he did. Turns out he donates because his dad, my Grandpa Bill, was a long-time blood donor.
In my early 20s I set a goal to donate the largest feasible volume that was meaningful to me as a homebrewer: a keg. A standard half-barrel keg is half of a barrel (31 gallons), so 15.5 gallons or 124 pints of beer. Or blood.
I donated blood yesterday and checked my stats: 53 units with the Red Cross, plus 10 that I donated with LifeSource during the periods I lived in Chicago. That puts me one unit into the second half of my keg.