Using Used CB Fertility Monitor.. How to set and when to test?

[melewen]

Hi ladies! I bought a used CB Fertility Monitor (from someone in the same city) and it came with 9 free sticks. I usually O around CD18 so I don't think I would need to start testing as early as CD6, but I don't really know if that's how it works? I reeeeally don't want to have to buy a new pack of sticks this month as we have already spent so much on TTC (acupuncture tomorrow!!), and if I start on CD6 i'll need another pack of sticks.. So when do you suggest I start testing?

Also, I have no earthly idea how to reset the testing window, and I can't find anything online or in the book. Anyone know how to do this?