Jennifer,
I am currently using Bigger with my 12 yo ds, 10 yo dd, and my 7 yo dd. I do have the older two do the extension pack on their own and they do math and English at their individual levels. I am finding, at least for us, that the books that are included are well within their reading levels and that this program has been enough of a challenge for them. I do not add anything and feel that it is "beefy" enough for them.
I am looking forward to eventually moving on to Preparing with them and am planning on just using what is provided along with the extension pack. That to me is the joy of living books... good literature is good literature.
I hope that I have been a help to you. Blessings as you begin your new year. The great thing about HOD is that once you have the books, you're good to go. There is not a lot of prep work, so there is no need to "feel behind".
