title: Should I aim to add a class/id to everything, or use other selectors
body: <p>I'm never sure what the best (most efficient) way to select an element is.</p>
  
  <p>Lets say I have the following layout (extremely simple example)</p>
  
  <pre><code>&lt;div id="navigation"&gt;
    &lt;ul&gt;
      &lt;li&gt;Link 1&lt;/li&gt;
      &lt;li&gt;Link 2&lt;/li&gt;
      &lt;li&gt;Link 3&lt;/li&gt;
    &lt;/ul&gt;
  &lt;/div&gt;
  </code></pre>
  
  <ol>
  <li>I want to select my unordered list (ensuring I don't affect any other UL's throughout my site), should I do <code>#navigation ul {}</code> or assign a class to the UL?</li>
  <li>I want to select my list items, again ensuring I only affect those. Should I do <code>navigation ul li{}</code> or assign a class?</li>
  <li>And finally, If I want to select my first link and style it, should I do <code>#navigation ul li:first-child {}</code> or assign a class?</li>
  </ol>
  
  <p>I appreciate these questions are pretty much the same, but I'm curious when you should use a class and when not to. </p>