The current crop of long-acting antiretrovirals (ARVs) in development, which hope to require only monthly or quarterly dosing, could increase the life spans of people with HIV, especially those with low adherence to daily regimens. Using mathematical models, researchers projected that, on average, long-acting ARVs would increase life expectancy by 0.5 to 0.6 years when compared with standard ARVs. For those with low adherence to standard ARVs, however, the benefit of switching to long-acting drugs would be an extra two to three years of life expectancy. The models also suggested that long-acting treatment would be cost-effective for those who have a history of poor adherence and who fail multiple regimens. Giving these therapies to those with lower adherence would increase its relative cost-effectiveness.