We only had it tested whenever he went to the vet. It fluctuated so rapidly, that it was not practical to test it very often. We kept him on a regular insulin schedule of two shots a day, and he became so used to the routine that he would even jump up on the table and wait for his shot. Mostly we watched how much water he drank, and used that as our gauge. I seem to remember that when he drank more than usual, the vet had us increase his dose a little. But you'll want to ask your vet about that, of course.