How long does it take to get better at tactics?

I've been practicing with Tactics Trainer a lot (40 hours since Nov.3rd). I thought I was getting better. But, I played a game earlier today where I could have won my opponents Queen, not once, but twice, and I didn't have a clue either time. Granted it was a 5-minute game, but I never considered either move. At what point do you stop missing obvious moves?

16Bh7 Kh8. I'd advise working a lot on a small number of tough positions, taken from good games such as Alekhines...that can be found in books.

16. Bh7+ Kh8 17. Nxf7+ picks up the queen likewise (and no, I didn't see that dureing the game either). Any suggestion for specific titles to look at?

1.5 years and still waiting.  

10,000 hours to become an "expert".  

Must be somewhere in between if I am considered average.

But pattern recognition is huge...your first miss looks like that Petroff trap, so people who are familiar with it may recognize that tactic in a slightly different situation.   

I am sure if you keep doing what you are doing for a year, you will dominate 2-3 move tactical sequences like they are nothing.

The only book that helped me a bit with complicated tactics : Alexander Alekhine, Master of attack, by Raetsky and Chetverik, everyman chess. The puzzles start quite simply, it gets harder as you move on, there's a section with hints to help you make the puzzles a bit easier if you don't succeed, plus for every position, you get the whole game from where it was taken, so you can also work on opening principles and see how tactical possibilities arise...

I would like to point out that your mate at the end of the game, with the rook sacrifice, is pretty much a book tactic.  If you hadn't been doing tactics, would you have seen that?

i stopped playing for a yr and a half ish and my rating was approx 1400 + now its more like 1000 + i cant see moves i could see then.... but then when i played i played with my friends at least 2 hrs a day 5 days a week for a whole yr...

so..... now since i juz picked up chess only in nov of 2010... i have had to start from scratch... 

I play 1.d4, but have not tried 2.Bf4 followed by 4.Bg3 before. It looks like a nice way to get the dark squared bishop outside of the pawn chain without waiting for Black to play Nf6, and then White playing Bg5, pinning the knight to the queen.

1.d4 d5 2.Bf4 - D00: Queen Pawn Game - Mason Attack.

No, sorry I wasn't clear about that. I've been playing and studying for 40 years. I've been studying tactics with Tactics Trainer for a couple of weeks. Maybe I'm just getting worse as I get older.

Do you have a USCF rating?

I briefly hit 1800 back in 1996, and my last official rating as an active tournament player was 1731 in 1998. I'd like to get back into tournament play while I still can.

I'm 50 years old and have time to devote to chess. And, while I know any real achievement isn't likely at this point, I'd like to at least feel that I'm competent at the game I've spent so much time on.

Why did you quit? I notice you haven't played but a couple games on hereeither, even though you've been a member since 2008!!!!

OK, our first example is going to be very very simple, this is just to get it started

http://www.youtube.com/watch?v=M_okqyKTD-4

I quit because of time, work, family issues. What games I've played have been on FICS, and my membership hasn't been continuous, I first joined in 2008, let it lapse and rejoined less than a month ago.

 OH. I learnd several months ago after I started this account, but still suck at it. I just took it up because I heard it improves your concentration. Though I don't know if that's true or not.

Getting back to the OP, I suspect that you were too intent on following the opening preparation and playing thematic moves to notice the opportunities in a 5 minute game. The problem is not with ability. The problem is the time control. Five minute chess is not chess. Shrug it off and play a few long games. That will be a better measure of your tactical ability.

You may be right about that, actually. At move 9 I saw that I could set up the Stonewall with 9. f4 and really didn't look beyond that.

AIKIDO CHESS!

The best video ever, for a begginer like me =)

Here is part of your problem.  Blitz chess is basically junk chess.  It can be fun, and it is no doubt popular, but it's counterproductive to true improvement.  You don't have the time to look deeply into a position; you don't have the time to go through any kind of organized thought process.  You see, you react, you guess.

Don't confuse that sentiment with an elitist opinion.  I certainly do not think less of players who enjoy blitz or bullet games, or that "their" game is any less meaningful than mine.  However, if you really want to improve your overall skill, blitz isn't the place to do it.  Most strong players and teachers would agree with me.