Continuous glucose monitoring (CGM) was used in 9% of 17,317 participants (6% of children <13 years old, 4% of adolescents 13 to <18 years, 6% of young adults 18 to <26 years, and 21% of adults ≥26 years) who replied to a CGM device use questionnaire 1 year after enrollment in the T1D Exchange clinic registry (1). This is the highest penetration in a large patient population reported so far, demonstrating the increased use of real-time CGM in an advanced medical environment. Moreover, CGM use was associated with lower HbA1c in children (8.3% vs. 8.6%, p<0.001) and adults (7.7% vs. 7.9%, p<0.001), but also with a more affluent social status (1). Interestingly, only a quarter of self-reported CGM users downloaded data from their device at least once per month (1), indicating that the general CGM use largely remains intuitive. Regular CGM device downloading is associated with a considerable improvement in metabolic control (2) and may be one of the important determinants of sustained and efficient routine CGM use in T1D, also for prevention of severe hypoglycemia. However, many controversies remain in the population of non-insulin-treated patients with T2D, where a well-designed clinical trial investigating the use of CGM is yet to arrive. The present review focuses on the most recent articles describing factors that improve glycemic outcomes in persons using CGM as well as how CGM is being utilized to understand the progression of normal glucose tolerance to impaired glucose tolerance and to overt type 2 and type 1 diabetes in certain high-risk populations.