The utility and usability of some everyday objects improve through use. For example, the bindings of cheap paperback books act as automatic bookmarks in the sense that they crack at the last page read. Through use, baseball gloves and leather shoes conform to objects they are intended to contain. The polished areas of otherwise patinaed brass door handles reveal where others have succeeded in grasping them. The most often consulted pages of many linear feet of auto parts store catalogs are identifiable by smudges, familiar tears and loose pages.
You read in bed. You reach for your book.
Where did you leave off last night?
You fill orders in an auto parts store.
Where are the spark plugs?
You want to bake that special cake.
Which recipe card is it on?
You are a software programmer. You never remember all the arguments for text output.
Which manual page are they on?
When feasible and cost-effective, we ought to design digital objects so that their utility and usability improve through use. For example, automatic change bars cost little and improve a draft document's editability, especially in later stages when the ratio of changed to persistent text drops and the changed portions are otherwise harder to identify.
Copyright 1994 Bell Communications Research