It’s been at least 4-5 years since it’s been a resource used here at home. I don’t recall it taking all year.
Suggested use:
Begin by going over how you’d like it to be used. Will it be with Mom, or independent? How many days/per week would you like grammar study to take place using EG+? Do you want to to be completed in one year, or spread out longer?
As with other resources, consider how much can be reasonably expected to be completed successfully on an independent basis within the amount of time you wish to allot to it. If 20 minutes is the time you plan to devote to it, set a timer on those days, for that many minutes for a week, or two. This should give you a fairly good idea how many pages are a good fit. Then, take the number of pages left in the book, divide that by the number of expected pages and you’ll know how many days it will tame to complete. This will still be a guesstimate. Adjust, up or down, the number of pages, or days, to cover it within your goal time.
That may be a long answer, but each of my older children finished it at different times. One didn’t complete it as he preferred OMT and I felt cofident that it was plenty formal grammar for him. I also felt EG+ was enough for one of our other sons.
My answers tend to suggest tailoring to each child’s needs/abilities more than to standardized timeline goals. Hope you’ll understand.