Every year Sonlight must replace books that have gone out of print, or we may find a book that better fits our standards or goals for a particular curriculum. Also, because client input is such a valuable resource for us, you will find that each new Instructor's Guide implements many suggestions we have collected from Sonlight users over the previous year. Also, as the original purchaser, you will be eligible to upgrade your IG for life at a 50% discount!
For the reasons mentioned above, we recommend you purchase a new Instructor's Guide.
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Sonlight upgrades their instructor's guides (IG's) each year. Sometimes this involves major changes, sometimes the changes are minor, but there are always changes. Book selections may have changed, the order in which the books are read may have changed, and/or there may be changes in the order in which concepts are introduced. Our recommendation is to purchase the same edition of all instructor's guides. Purchasing the same edition will prevent any problems that might occur.