PWM Frequency

First, I don´t know if this is the correct section to post this, if I'm wrong, sorry.

So, I need to change the PWM frequency for a project and found this:

http://forum.arduino.cc/index.php?topic=117425.0~

My question is (dunno if its a silly one), will it change the frequency for good? Or the second I load a code without that lib, will the frequency go back to arduino's standard?

It will reset to the standard when you load a new sketch.

If you comment out the #include statement for that library it will load the sketch WITHOUT that library. (duh)

Thx guys, I had a feeling it would be a stupid question, but deep down I feared that it might change something in the controller permanently