I don’t know much about how healthy it is for you, never heard that before, its not like changing your oil or something. Either way, they ask you a shit load of questions and one of them on there is “have you ever stuck yourself with a needle for non-medical purposes.” Weather or not you lie is up to you, but what is the point. IMO, its not worth it, you don’t need to give blood that bad. Plus if you are talking about the STD’s thing you can do a search online and get a STD test for nearly nothing.