Should I ever use display: block, or should I always use display: flex?
<p>I have recently been learning a lot about flexbox, but one thing is still unclear to me. Should I always set the <code>display</code> to <code>flex</code>/<code>inline-flex</code>, or is it ever advantageous to use <code>block</code>/<code>inline-block</code>?</p>

<p>I have found several useful articles, but none of the articles answer this specific question. <a href="https://stackoverflow.com/questions/15662578/flexible-box-model-display-flex-box-flexbox">This article</a> explained the difference between the different <code>display</code> values using flexbox instead of comparing them to <code>display: block</code>. The question did state that using <code>block</code>/<code>inline-block</code> was outdated, but I haven't seen any other sources confirming that. If <code>display: block</code> was now outdated, I would have thought it would say so on <a href="http://www.w3schools.com/cssref/pr_class_display.asp" rel="noreferrer">W3 Schools</a>(not that they are always correct, but they seem to be a good source).</p>

<p>Several answers have mentioned <a href="https://css-tricks.com/snippets/css/a-guide-to-flexbox/" rel="noreferrer">this article</a>, but again, it doesn't explain when <code>display: block</code> should be used instead of <code>display: flex</code>(if ever).</p>

<p>Other articles answering <em>similar</em> questions are <a href="http://blog.karenmenezes.com/2014/apr/13/floats-inline-block-or-display-table-or-flexbox/" rel="noreferrer">this one</a> and <a href="https://www.quora.com/What-is-the-difference-between-inline-flex-and-inline-block-in-CSS" rel="noreferrer">this one</a>. While both are great articles. The first one gave advantages and disadvantages to both, but the only significant disadvantage of flexbox was browser compatibility which isn't a concern for this project. The latter article gave the best answer I saw which was that using <code>display: flex</code> allows the element to retain flexbox properties. Does that mean that if it doesn't need flexbox properties I should just use <code>display: block</code>? Does either have a performance impact, or should I just always use <code>display: flex</code>?</p>