title: Is there a minimum string length for F() to be useful?
body: <p>Is there a limit for short strings where using the <a href="https://stackoverflow.com/questions/16597437/arduino-f-what-does-it-actually-do"><code>F()</code></a> macro brings more RAM overhead then saving?</p>
  
  <p>For (a contrived) example:</p>
  
  <pre><code>Serial.print(F("\n"));
  Serial.print(F("Hi"));
  Serial.print(F("there!"));
  Serial.print(F("How do you doyou how?"));
  </code></pre>
  
  <p>Would any one of those be more efficient without the <code>F()</code>?</p>
  
  <p>I imagine it uses some RAM to iterate over the string and copy it from PROGMEM to RAM. I guess the question is: how much? Also, is heap fragmentation a concern here?</p>
  
  <p>I'm looking at this purely from SRAM-conserving perspective.</p>