How To Decide Which TOG Books to Buy

This has been a busy week for me, not that it is reflected in what we did. Our annual homeschool convention is coming up, so I've had to look at what I need for next year. The steps I took are as follows:

1. Determine what books can be gotten through our local library or inter-library loan. (We have an awesome ILL system here!)
2. Determine, of the books that are available through the library, which would be better to purchase based on the length of use versus the number of copies available. With TOG, if the book is used for literature, and I need it for longer than two weeks, I will place it on my list to consider purchasing it. Or if there is only one or two copies, and I need it for longer than three weeks, I will consider purchasing it as well.
   
3. Of the books that we do not have, I look at how many weeks it will be used. If I will be used for more than two weeks, I will place it on my list to consider purchasing it.
4. I will then look at the books not available that are one or two weeks in length. First I will look to see if there is an alternate book for that level available from the library. If it is not, I will see if the book a level below or above is available. If the level below is available, then I will put that on my list with a note that I should look for a few other books from the library with the same call number to fill in the blanks. If there is still no luck, I will place it on my list to consider purchasing it.

Now I have a much shorter list to bring with me to the homeschool convention. Right now, there are only about ten books on it. It is a lengthy process that I usually begin in January with the goal of being done by mid March when we hit spring break time. That way I can focus on attempting to end the year on the upswing rather than dragging.