When should I do extra blood glucose monitoring if I have diabetes?

You should do extra blood glucose checks under the following circumstances:

•   when you’re ill

•   if you suspect low blood glucose

•   before you drive (if you take insulin)

•   when you have trouble recognizing the warning signs of
    hypoglycemia

•   when you’re physically more active than usual

•   if you start taking a nondiabetes medication that affects blood
    glucose levels or your ability to recognize low blood glucose warning 
    signs

•   if you have insulin reactions at night or wake up with high blood
    glucose levels

•   when you are changing your insulin plan, your meal plan, or your
    exercise routine

•   when you have lost or gained weight

•   when your levels have been outside your target range more often
    than in your range