I know that you use Illustrator for your logo's, Photoshop for you pictures (to edit them) But for what purpose do you use inDesign? If it is for logo's and design, why does Adobe make another program when they have Illustrator already?
Photoshop is for editing bitmaps (though it's become more than that now)
Illustrator is if creating and editing vectors
Indesign is for layout of bitmaps and vectors
Simplistic but that's about it