Do u have to format the sd card everytime u switch it out.? or once u format it the first time its fine?

you don't need to format it each time, just do it when you are ready to delete your old pix.

I found that if i didnt format it that the camara would not take pics?

you do not have to format every single time, but you have to properly erase your old pics. Don't delete the folder, just delete the pictures in the folder.