How long to master a single opening?

It depends. I know, but let's say for an lower average player like me ?(1500-1600)

Is there any merit in learning a single opening for white and one for black really well before trying to learn bits of several openings and defenses at once?

What would someone with a title consider to be sufficient time to learn a single opening properly?

And I think my next question would be : Which two openings do you consider best for white and black?

The time between learning an opening and actually using it in tournaments is quite large - you can learn it, but then you'll also want practice. It takes maybe like 20 hours to learn an opening, but you may not know all the intricate details about it. As for the two openings, it really depends on taste and style

Looking at your past games, I'd say your current openings are more than fine. If you are interested in changing your openings, though, it probably shouldn't take more than 5 hours of dedicated time. Maybe something you could do on a free weekend or two.

Thanks guys, I recently got back into chess. I have forgotten what an incredible game/art it is and how frustrating it can be. I suppose I am looking for a quick way to make up for lost time :)

At your level (going strictly by your chess.com rating) there is no need to invest the time and effort into thouroughly learning an opening.  Study the pawn structures associated with the openings you want to play.  That way you will understand why each move is made, and why each piece goes where it does. 

As far as what openings you should play?  Thats up to you, as they have to be openings your comfortable playing.

Some openings are more complicated and have more variations than other openings. For example it might take a month of study and practice to learn the Ponziani but more like ten months to learn the Ruy Lopez.

To learn the English [1. c4 ] could take a year.

Of course it depends what you mean by "learn"...

A few moves of the Ruy Lopez is all I can remember from school. When I win it is normally because my opponent knows as little as I do.

I think it also gets more difficult when you are working all week and don't have time or energy at night to work through chess books.

Then again with some luck I am going to be somewhere in ten years from now , it might as well be with the knowledge of a few openings studied on weekends.

I can only give myself as an example, but i made it to USCF A class on nothing but opening principles, learning pawn structures, knowing how to formulate a middlegame plan, a lot of end game study.  I honestly think your chess study time would be put to much better use than openings. 

Thanks Diakonia, that definitely gives me motivation. Someone told me once that some chess teachers teach chess starting with the end game and finishing with openings. Don't know if it is true. What you say makes a lot of sense though.

Thats how i teach, ending first.

One reason to study openings is that most chess games of players rated 1700 or lower are winning by one side or the other by the 13th move.

By this I mean that by the 13th move, one side or another will have a winning advantage.

While knowledge of endings is important, it is also very helpful to know how to play the first 13 moves.

Youre very welcome.  There is  quote by one of my favorite players that sums up the importance of the opening.

The opening serves 1 purpose.  To get to a playable middlegame.

Lajos Portisch.

Thanks all for taking time to give me advice. I will keep on keeping on.

This post is quite old, and hoping you are still playing these days, I want to give my example and my way. My rating keeps fluctuating between 1800+ and 1200. Ya its a strange case. But its because sometimes I take years of gap. I love this game but my life sometimes get messy and I loose the track. FInally I am back again with conviction to give daily effort to improve. 

This is how I go from 1200 to 1800 (before going out of touch completely again and again). I start with tactics. A daily problem solving (20 standard tactics of hard level in chesstempo) with an accuracy of 90% will give your rating a boost which you can't imagine until you do it. But 90% accuracy is must!! Then study endgames thoroughly. Calculate every possible line and till end. That develops your brain's calculation ability and eyesight. Forget about openings till you are at least 2200 in chess.com. But if you really want to learn, choose your opening, play a game in that and analyse every possibility post game. Thats the shortest and most interesting way to improve effectively!

With videos, its pretty short, (videos like these):