I've been donating blood regularly since my mid 40's, sorry I didn't start sooner. However I would urge anyone under 67 to start donating if they can because once started and on the register you can continue indefinitely. My enthusiasm for Blood Doning is based on altruism and also self interest.
As we get older our blood thickens and we become to ailments due to "stale" blood, thrombosis and strokes. The risk of these is greatly reduced if you donate regularsly.
Recently the blood service has started sending you an email saying which hospital your blood has gone to, you do not know the patient but you do know that you are helping others and may be saving a life. I am white British aged mid 70's but my blood is more common in ethnic minorities so one of its main uses is in treating Sickle Cell disease. If you or one of your friends belongs to an ethnic minority where blood donors are especially needed encourage them to register and donate if they can. Blood Donors are in short supply especially after Covid so anyone who can give blood and doesn't should, remember that 25% of us will need blood at sometime in our lives.