Better to have 2 extra rounds and not need them............than to need 2 more rounds and not have them.
Obviously, but your logic doesn't track. Why not say, "Better to have 100 rounds and not need them..." We could go on and on. My question is why does the OP feel that those two rounds will make him better armed?
The average rounds used in most self defense situations is quoted as being 3-5 IIRC. But just remember if a dozen people used 3 rounds, to get that average it means someone used 15.
Mathematically speaking, if 11 took three shots the 12th had to take 27 to make an average of 5, but who's counting?
I've learned a few things this year. The most shocking statistic I've discovered is that the most common number of shots fired when a gun is used to end an assault is ZERO. In fact, what I discovered is that the number is something like 98% of all instances, where a gun is used to successfully defend against some kind of assault, no shots were fired. This surprised me greatly.
Which of course leads me back to the original question, how valuable are those two extra rounds?
I can just hear it now, "If they saved your life they are invaluable." Obviously, but please, let's discuss this not just throw out colloquialisms. I carry 8 rounds with an 8 round extra mag. I don't feel under gunned. I don't carry the extra mag for increased capacity, but in the unlikely event of a malfunction.