One reason why, white should castle immediately is because white is threatening to play d4! And, then open the position up. Also, half-open, as well as open files are ideal for Rooks!

Sorry DustinKinney, You are Grossly Mistaken again. You have shown that your positional evaluation skillls are beginner at best.

You also gave 100% incorrect advice to another beginner regarding the best route to take towards improvement, suggesting that Endgames, Positional Awareness, and Tactics should be secondary to studying Openings. I, RonaldInho, And JacksonWShowalter pointed out your error, though you persist in your defiance. (Between the three of us, we probably have 90 plus years of Chess experience.)

If you really want to learn from these discussions, as you said that you do, then maybe an honest approach would be a good start.

I'd play d3 or 0-0 in this position with white. But I don't see much fault with a4. Sure, d3 and 0-0 are a bit 'faster' and more principled, but that doesn't remove a4 from consideration.
As Larsen pointed out, pushing rook pawns up two squares can be useful. Black has to make up his mind rightaway now, go 0-0-0 or 0-0 manually via Kf7-Kg8 (the a2-g8 diagonal isn't as deadly without the bishops), he can do both here and in both cases white can send some pawns and pieces after the black king. I've known players who'd keep the king in the center scared to death of going either side with the king. That may be a motivation.

If it's a move white made very fast, you could consider it a waiting move. It grabs space obviously and there are some side-effects that wouldn't come into play. For instance, a rook-lift via a3 (or heaven forbid doubling on the a-file if black 0-0-0) the bishop ending up on b2 or a3 (which may be relevant if black commits to c6) after the b-pawn moves up, outposting the Nc3 on b5 or retreating it for some purpose to a2.
On the other hand, white is giving black some information too, he's going to go kingside, staying in the center isn't a real option and going long is just bad.

Bottom line, a4 isn't bad, but d3 and 0-0 are better.

I agree. My evaluation skills are beginner at best. And therefore, it is your responsibilty (obligation) to help teach me. [where much is given, much is expected]

Note: This doesn't mean that I will not use what I know, to help teach others, trying to determine each solution indivdually ; but I obviously do need help! Would you please help me? (And by help, I mean teach)

And, Also, I want to have an open mind about this, but I am 90% hard-headed. So, I may be difficult at times! This will be a challenge for you! Are you up for it?

I agree with Perseus. The move is very much a "I double-dog dare you to castle queenside" move. It is probably not best here - and would be definitely bad if black could castle short.

Beyond that, however, we can't generalize. In the Ruy Lopez, white plays a4 to create weak pawns to attack. In some sicilian variations, he plays a4 to restrain black's queenside advance, or to secure the b5 square for a N.

Actually, Fritz gives + 1 to both lines on my system.

So one is as good as the other.

Best Of Luck!

Thanks for all the help!

o wow this all seems so difficult to learn

a4 also prepares for (threatens)Ra3 aka a rook lift

Probobly because you play amateurs and they see GM's playing a4 and h4 so they follow their moves like sheep because they can't think of their own plan.

That's my guess.