In ancient times the distance between farms and homesteads could sometimes be great, and individuals would perform rituals as a family unit using practices that were handed down to them from generation to generation. I am certain that over the years these rituals were modified to suit the individual family unit, and differed from household to household. They called to their Gods a millenium ago for the same reasons that we do today. From their hearts they called to their Gods to honor them out of love, necessity, desperation, and even fear. In those ancient times they had much more to fear than we do today. They literally lived and died by the yield of their crops; they feared invaders to their lands, and even those who attacked from within; and disease was a constant companion to our ancient ancestors. I am absolutely sure that when they called to the Great Physician Goddess Eir for instance, they did not care about a formula, or some method to ask the Great Goddess to help their loved one. They simply took a ritual that they practiced often, and adapted it for the purpose at hand, and asked from the heart for the Goddesses help.
Did the Gods think less of our ancestors because they honored them in hundreds ( maybe even thousands) of different ways ? Of course not ! Whether a ritual, blot, or sumbel lasts for just a few minutes, or hours, makes no difference. Nor does the content, as long as it is respectful, and comes from an honest heart. This is just an unverifiable personal gnosis ( UPG ), but I think that some of the Gods and Goddesses actually have a sense of humor, and if something minor goes wrong during a ritual they are amused. Thor in particular I have always felt seems to enjoy my embarrassment when something does not go quite right during a ritual. Most particularly my earliest rituals, some of which did not go quite as planned.
These books that are written by these authors can be informative, and entertaining as well, but be forewarned that the Gods want you to follow them, and not these authors. They want to hear what you have to say, and feel the love and honor that you have for them. They do not want you to express yourself through someone else. Your imperfections mean more to the Gods and Goddesses, than do the supposed perfection of these authors and their words of absolute truth. Read them, and enjoy them, but do not bring them to the altar when speaking to our Gods !
Go with Odin's wisdom, Freyja's love, and Thor's protection !