Moonnie, but Yusupov advises to switch to the Petroff ( 1. e4 e5 2. Nf3 Nf6 ) in his series.
He does not, he says that if you already have an opening you're happy with, then it's fine to stick to that. Yusupov's chapter on the Petroff (and on other openings) are more an example of how to study the opening in general, as well as a short primer on some Petroff lines.
Okay,
well in my case at least I was not happy with the positions I was getting out of 1 ... c5 (due to my own shortcomings), so switching to the Petroff when I saw that chapter was great for me.
I certainly wouldn't switch just for the sport of switching.
Like i said before. If you want to better understand positions get a series like Chess Evolution from Jussupov or a book like My System (Nimzoitisch) instead of learning opening moves without understanding the concepts explained in these books. You will learn faster and lose less rating in the process.
No need to get offensive and claim I just copy moves in some sort of braindead state...
This is a typical chess cliche: 'you need to know to know the ideas of the opening, don't copy moves like a monkey'
The statement on its own is correct, but people interpret it as if it's some kind of choise. You just need both, you can't play a Dragon with black based on general ideas, you need concrete move orders. You have to know offbeat stuff where your best move is something weird.
I really need to play some practise games against strong opponents to get used to some opening. Maybe you don't, good for you and you're probably more talented then me.
why play more than one opening? because stronger players will prepare and weaker players will go for drawish lines. I also dislike some of my current openings and I want to change them.
I'm just saying that I wish that I would have switched openings earlier on, so I had a basic feeling already. Instead of playing something I never played, against people who are experienced in that line.
First of all i fail to see where and why my post is offensive.
Second the original poster asked if he should switch to e5 to improve his chess and knowledge of certain structures. Learning as you call it "concrete move orders" and "offbeat stuff where you best move is something weird" is clearly not going to help him understand anything more about chess. I only said there were better ways to improve your chess then learning different openings.
Last but not least openings will not teach you important concepts like overprotection, strong and weak squares, square colour theory. These are important concept needed to understand why moves in openings are made and how to react if your oponent suddenly decides to not play theory.
Oww and everybody knows i play the most drawish openings ever like the Berlin Defence and the Nimzo but i still will a lot of games against prepared opponents.
The result of the opening is rarely important at our level. It is understanding the dark square strategy in the nimzo and the light square strategy in the berlin that win games.
First of all i fail to see where and why my post is offensive.
I just get offended very easily, I'm like the chess CIDI ;)
Never said that our TS should study theory extensively, I was just replying on your post to me.
But whatever, let's agree to disagree. I advise switching openings to play different structures, you advice sticking to your main opening and learn different structures by studying books.
Both could work, you're not gonna convince me and I'm not gonna convince you, that's fine
Well I don't think you should play stuff you don't like... But even GMs make ?! moves. The idea that your opponents will gain an advantage and seal it for forty moves because you forgot one just seems unlikely. You could have a crap position for sure but that can happen just as easily in the other parts of the game. Anyway I started playing 1...e5 and don't know much theory at all. I can last around 5 or 6 moves at most before I'm on my own. However I don't play the super-crazy gambit stuff either so maybe that has something to do with it. I don't play that boring Berlin either. :P
I also found a collection of games and I haven't finished looking at it yet but there are a lot interesting strategies and motifs and they become more complicated the further down the list you go:
http://www.chessgames.com/perl/chesscollection?cid=1006294
At what rating range? I generally play people up to 2100 or so in the KNSB leagues, and nobody ever plays highly theoretical lines where concrete move orders and so on are critical.
Personally I want to play some line in the Classical Sicilian, but all white players so far have deviated from the main line before move 8.
Is it worth the switch, though?
I'm quite content with playing the sicilian, but am just curious on whether switching to e5 will improve my chess understanding.
It's a long term investment. The positions stemming from 1...e5 are probably more diverse than those you'll meet playing the Sicilian. If you play competitively, and are young it may make a difference in 7-10 years. From a positional point of view, 1...e5 is probably somewhat richer than 1...c5, which is more of a streetfighting avenue 
The openings don't help much in the middlegame. The whole familiarity argument can only hold for so long because soon tactics and other considerations will force a change in the game. And then there is the chance that the opening goes in a direction you've never encountered.
True in a sense, it just depends on how well someone may have studied the variations to their preferred opening.