title: PHP: where should I put my includes?
body: <p>I have coded a set of basic functions I'm using in various scripts, but very seldom more than once in the same script.</p>
  
  <p>Since I was schooled only in compiled languages programming I may not fully understand the dynamics of interpreted / JIT compiled languages: When using apache's PHP module, is each instruction compiled and then executed (like it happens in the CLI, for example), or is the whole script JIT compiled and then executed?</p>
  
  <p>In case it's per instruction compiling/executing, should I have a block of <code>require_once</code> at the beginning of the file (which seems way more sane to me) or would it be more efficient to include them only if I need them (inside <code>if</code> blocks and so...)?</p>