Why does my cigarette lighter keep blowing fuses every time I plug something into it

First make sure you have the right size fuse in it look at your owners manual it should tell you what size to put in there sometimes people blow a fuse and replace it with a weaker fuse it will work for a while till they plug something in that overloads the fuse then blows and if they sell the car the new owners don't know this they just keep replacing it with same type fuse that's in it. Second make sure whatever it is you are plugging in doesn't have a short itself try plugging in something different and see if it blows then if it doesn't then you know where your problem lies.