This really depends upon the individual. Two people can get the same exact piercing and one person will bleed but the other will not.
Some individuals will just bleed slightly and other's will bleed quite a bit before it starts to clot and slow down.
People taking blood thinners are discouraged from piercings, as it is harder for their blood to start clotting and they could loose too much blood.
Here are two images of customers tragus piercings. They both got the same style piercing, but one girl had bleeding and the other had no bleeding.