I have to say we had the opposite experience from MissusLeata. I would say that by Thursday or Friday we might be tired of reading the same story, but the point of it when they are little is that they begin to make those connections (remember them, that is) each time the story is read, and you build on that thinking throughout the week. My daughter loves the books so much, that even now if she sees one somewhere she will say, “Oh, I loved that story!!”
I know a lot of moms who have done Five in a Row exclusively (adding in math and phonics, and building on science, obviously) for several years. Some move into Beyond FIAR, some stop at Vol. 4 of FIAR. Do what you think works best for you, but I would only enourage you to not worry about whether it is ‘enough.’ In many cases, less is more, and most moms who have used FIAR until even ages 10 and 11 find that the retention is awesome and would declare that it is, in fact, enough.
And you are right, it IS trial and error in these early years! I will say it would probably be more reasonable to give FIAR a chance before investing in a boxed curriculum. FIAR is designed for you to add in whatever ‘go-alongs’ you want to — non-fiction included. THe difference is that you are the mom making those decisions and going to the library and picking out those books, so if that is something you dread, it’s a point to consider. I found that to be one of the most fun parts of it, but I’m a former librarian and have only one child to teach.