Like "I think it depends. My mother, who is on insulin for type 2 diabetes, is always high, so , in "absolute" terms, if that exists, I'd say I would be worried about her constant highs. However, my dad and I were always brittle, and our blood sugar ranges were very erratic. So, for example , my blood sugar right now might be 100, but in 10 minutes it might be 299..typical for me, and was also typical for my dad. I'd say more damage can be done when the range is not consistent, because the blood vessels suffer terribly in the heart and organs, then. But, with a type 1 diabetic, who must have insulin to survive, they are in a chronic state of " the body will die soon" if they do not take their insulin. When you move from blood sugar reading A to blood sugar reading B, and the range is erratic and huge, the organ damage would be much more serious. But, when you are in an absolute state of " going to die" if you don't take your insulin, always severely high , I don't know--my strong opinion, and I could be wrong, is, if a person has inconsistent blood sugar levels that are erratic, this the, the difference matters the most. I am not a doctor or nurse...ha,ha....ANNE"