As I said. I'm still learning, but it helps me to get decent prints without making loads of test strips. I tend to make a print, and then possibly make another if I decide it can be "improved". The biggest thing I have "learned" is that the "highlight" reading must be on a not-quite-white highlight. If you choose to measure the highlight from the shadow of a very dense part of the negative that is blown out, the time is waaaaay too long. However, with a bit of practice it is a VERY useful tool, and I certainly wouldn't want to be without mine!