When I was originally diagnosed with type 2 diabetes, I was asked to take my blood sugar twice a day. One - fasting in the morning, and two - two hours after my biggest meal. But then the dr also added when I didn't feel well or "off" or whatever (which was quite frankly all of the time because I had diabetes and was freaking out a little). I knew that type 1 diabetics were supposed to test before driving so I threw that one in sometimes too.
I think one of the major differences between type 1 diabetics and type 2 diabetics is how often they test their blood sugar. I've asked type 2 diabetics how often they take their blood sugar and it follows the routine I listed - at most twice a week. I hope those who are dosing insulin take their blood sugar more often, but I wouldn't bet my life on it. Type 1 diabetics are supposed to take their blood sugar fasting, before each meal or snack, before driving, before bed, when sick, when they feel "off", etc. And when you have a blood sugar number that needs adjustment, like you were low and ate something, then you have to re-test so you end up taking your blood sugar again! Sometimes the number seems off so you have to wash your hands and take your blood sugar yet again! Did you get an error? That's a wasted test strip and then you have to take your blood sugar again. Argh, keeping up with blood sugar numbers is a big fat pain (but life saving). :)