Studies over the past 7 years have made it seemingly quite clear that relatively high levels of adherence to highly active antiretroviral therapy (HAART), in most studies levels > 95%, are required for the highest likelihood of successful therapy. While the HAART regimens used in these studies were generally non-ritonavir boosted protease inhibitor (PI)-based HAART, and therefore may not reflect the more forgiving pharmacokinetics of ritonavir-boosted PI or non-nucleoside reverse transcriptase inhibitor (NNRTI) HAART regimens, these data have been used as a guidepost by many clinicians and patients regardless of the regimen used.