title: What features any good application should care about 'By-Design'
body: <p>I know that the default answer is "it depends", but I want to know the feature list you are working from in developing a good application.</p>
  
  <p>I'm particularly interested in features that need to be cared about at design time because adding them late will cost us a lot.</p>
  
  <p><strong>Please list one feature per answer so we can vote for the most important features.</strong></p>
  
  <p>Any extra info, like your own war stories, will be appreciated.</p>
  
  <p>I ask this question to enhance my application from day zero, and I think I'm not the only one with this target, so please write whatever feature YOU think should be exist in a good application.</p>