title: Best practice to manage date and days
body: <p>I am working on a project where I have many operations to manage.
  Each operation have an end date and is composed by a certain amount of tasks.</p>
  
  <p>I want to display reminders (<em>a text displayed on the screen</em>) if a task is not done before <code>[end date]</code> - <code>X days</code>.</p>
  
  <p>All the data is stored in <strong>MySQL</strong> database and I work with <strong>PHP</strong> and <strong>HTML5</strong>.</p>
  
  <ul>
  <li>Which datatype is (<em>are</em>) the best to work with date and days (<em>to
  perform calculations</em>)?</li>
  <li>Can I work with <code>Date()</code> and subtract days in a easy way?</li>
  </ul>
  
  <p>I do not have a specific technical question, but I think sharing best way to proceed is a good thing, right?</p>
  
  <p>I'm curious to know what are the best ways to proceed and open to any proposal!</p>