3D printing can be a very useful technology, not only used to print vases and other "useless" items (i also enjoy printing "useless" items). Yesterday a holder, that attaches a rail that the shower curtain glides on, to the wall broke. I'm sure i could find it in a hardware store but since i have a 3D printer i decided to try and draw it and then print the part.
When designing something in a cad program if the part i'm making is a physical object and simple i like to make a quick sketch of the object on a paper so i don't have to measure it when modeling it later. I don't bother with making the sketch to scale or even good looking ;) The measuring was done with a digital caliper.