title: In Objective-C, importing same headers in every class make compile time longer?
body: <p>I'm a beginner of Objective-C/iOS programing.</p>
  
  <p>I want make a one header file which includes all class headers I use in my project.<br>
  And import the header in every class header file.</p>
  
  <p>Like this question:<br>
  <a href="https://stackoverflow.com/questions/1517146/">Including multiple classes in the same header file</a></p>
  
  <p>But does this approach increase compile time?<br>
  Or are there any other disadvantage?</p>
  
  <p>Please tell me the good ways to import headers.</p>