Is there a moment when one wants to put quotes (' or ") around numbers in php?

Fort example:

if ($_get["ssd"] == "0")

or should I put it?

if ($_get["ssd"] == 0)

Why do I want to put quotes around the 0?? Well, simply cause as you all already know, $_get vars are always strings!!

So in fact if $_get["ssd"] is empty, if ($_get["ssd"] == 0), will be true!! Problem here!!

Thank you!