First of all, blood donation is harmless to the body. I have been donating blood regularly for 10 years. I know many regular blood donors who have donated blood regularly for more than 10 years, and their health has not been harmed.

Secondly, blood is special and needs to be safe and fresh. Unlike old clothes or money, it can be given directly to people in need. Blood needs to be collected, tested, separated and stored, and the expenses incurred by these procedures are paid by patients. Patients don't have to pay for the blood itself.