Studying annotated game books

Maybe a stupid question, but here it goes...:

Chess teachers and authors (Dan Heisman) recommends playing through a lot of games, using maybe only 20-40 min pr. game, focusing on the main line and maybe not the detailed variations (depending on your own level of course!).

I am an improving player currently about rating 1550 (gained 250-300 points in 2 years) and I am starting to develop my own opening repertoire.

My question is; Does it make sense to go through game books with openings different from my repertoire? E.g. I play d4 as white and sic as black. I have "Unbeatable Chess Lessons" which does mainly have The Spanish and other e4 openings, but only a few similar to my repertoire.

I think going over games containing your repertoire openings should be more beneficial. But I have made the mistake of restricting myself to a very, well, strict repertoire for a long time, and I realized I've been missing a lot of other stuff. I'm making a switch and it's more painful than it ought to be. I'm not recommending to play king's gambit one day and then some timid english the other day, but just make sure you don't limit yourself religously.

I choose tournament books or biographies, but I use Chess Informant and my databases to go through many games in my repertoire. Although having a repertoire becomes important as you near master, it is important to avoid a rut and remain open to new openings. A good biography collection, such as Vladimir Kramnik: Life and Games or Karpov's Collected Games, 1961-1974, will have a more limited range of openings than a good tournament book, such as Zurich International Chess Tournament 1953. But, even a strong player's biography will reveal a broader range of openings than most amateurs are likely to study if they limit themselves to their own repertoire.

Thanks for the answers.

I will continue reading game collections and not be concerned playing games with opening I don't play (at the moment!)

"Does it make sense to go through game books with openings different from my repertoire?"

Absolutely it does! Practically speaking, annotated games of your repertoire will marginally improve your tournament results compared to not. But you can't restrict yourself for learning about the middlegame and I strongly encourage you study games from all openings to understand a variety of plans, because thematic ideas in your opening will not always be good depending on what your opponent does so you still need a more general understanding of strategy.