How long do I have to keep my new earrings in?

I just got my ears pierced for the third time in my life. The first time, age 8, I had to get the earring fastener surgically removed because my skin grew over it and the sticker closed it up and the other one closed naturally. The second time, age 10, they closed in a week after I took them out. (I was suprised too. I mean don't they stay open for a while?) And this is the third time, age 20. I just want to make absolute sure that they stay open.