What are the disadvantages of simple machines?

Simple machines usually make work easier by lengthening the distance the object being moved travels. If you want to raise a box up 5 ft by using a pulley, you will actually have to move 10 ft of rope, if it is a single pulley. Likewise, if you use a ramp, you have to move it an overall greater distance along the incline just to get it to the same height.