Dan in CA
With the new version of the program, it is good to have logging enabled because the irrigation timeline on the home page shows log data in a graphical form.
The reason I suggested using a new CD card was because daver had mention that he has been running his system for a fairly long time. SD cards can wear out after writing a lot of files to them as explained on the wiki:
It is a good idea to use a different media to store the log data. I use an 8GB SanDisk Cruzer Fit USB flash drive on my OSPi. It is small enough to fit inside the case with the cover on.