I respect the London System. I say go for it!
Should we always play the same chess openings? What do you think of playing only the London as white

@mickynj That is a good point! However, I have found that playing the London System really doesn't limit you all that much because if the opponent plays the Kings Indian Defense, you have a specific response prepared for them. If they mirror your moves, you have a completely different response planned out as well.
Even though the initial setup is basically the same, the middlegame can vary greatly from game to game.
That being said, I personally like this style of play. If you are more of an aggressive/tactical player you should go with another opening.

If you play the same opening all the time then you can rely on knowing more than your opponent and as a result can get a superior position.
London material that is possibly of interest:
https://web.archive.org/web/20140627074459/http://www.chesscafe.com/text/hansen85.pdf
http://www.gambitbooks.com/pdfs/Win_with_the_London_System.pdf
https://www.newinchess.com/media/wysiwyg/product_pdf/9035.pdf
https://www.newinchess.com/media/wysiwyg/product_pdf/7619.pdf
https://www.newinchess.com/media/wysiwyg/product_pdf/7767.pdf
https://web.archive.org/web/20140627100246/http://www.chesscafe.com/text/hansen139.pdf
https://web.archive.org/web/20140708093403/http://www.chesscafe.com/text/tips.pdf
https://www.newinchess.com/media/wysiwyg/product_pdf/7656.pdf
https://www.chess.com/article/view/the-perfect-opening-for-the-lazy-student
and there is also the book, First Steps: The Colle and London System.
https://www.chess.com/article/view/how-to-understand-openings
A set of London System DVDs by GM Damien Lemos.
A GM Simon Williams DVD on the same subject.
A set of London System DVDs by GM Henley
"... The whole structure of the game may be the result of the first few moves. For the sake of experience and practice it may be well to vary the openings, but for the sake of efficiency it might be better to stick to one single opening for the attack, and one single opening or method of development for the defence. This system may be followed until the one opening in question has been mastered. Then the player may take up a new opening, and thus gradually reach the point where he feels familiar with half a dozen different openings. Half a dozen different openings, well learned, are about all the average player needs to obtain good results. ..." - from Capablanca's Primer of Chess
"... Overall, I would advise most players to stick to a fairly limited range of openings, and not to worry about learning too much by heart. ..." - FM Steve Giddins (2008)

As noted the advantage to playing the same openings is comfort and familiarity. I think the possible disadvantage may be allowing your opponent to better predict your line of play if they study enough of your games.

"... The whole structure of the game may be the result of the first few moves. For the sake of experience and practice it may be well to vary the openings, but for the sake of efficiency it might be better to stick to one single opening for the attack, and one single opening or method of development for the defence. This system may be followed until the one opening in question has been mastered. Then the player may take up a new opening, and thus gradually reach the point where he feels familiar with half a dozen different openings. Half a dozen different openings, well learned, are about all the average player needs to obtain good results. ..." - from Capablanca's Primer of Chess
"... Overall, I would advise most players to stick to a fairly limited range of openings, and not to worry about learning too much by heart. ..." - FM Steve Giddins (2008)
Hi
it depends what you want to achieve and in which level you are competing . i guess any AGM FM GM does not limit themselves. But in our average senses where this gaming is just a hobby it does not matter at all if you stick with one or keep switching bcz your loss win draw nothing really matters. i used to play berlin , ruy , petrov and realised better switch to c4 or reti because my opponents knows lots of structure/move-order in berlin or ruy rather more positional into english. even one of the most successful GM kasparov switched his opening several time and many time surprised his opponents . he bring back evan's gambit and won a remarkable game against vishy.hope you would understand my view.
happy new year 2018
thx
cool
Currently, I'm playing only these openings, and I'm happy with that because I find it is easy to always play the same. There is an argument against this idea that states that we should try to play different openings to be a complete player. But I don't agree. We always have to meet different structures (you have the Reti, the English, the Bird, etc) and even within your main repertoire, there are many lines with different structures. Chess is very complex and by playing the same openings you control better some variables.