Even for low-cost improved stoves, which are affordable for all except for the poorest households, affordability still serves as a brake on faster market development. The time burden on women and children may not be a sufficient disincentive for men who have a greater voice in major purchasing decisions.76 Households that purchase fuel tend to rely on biomass fuel collection in parallel. This form of device 'stacking' makes it harder to see positive health or environmental outcomes. Decades of policy experimentation around the world has shown that private finance will not be able to address the infrastructural needs of the large segments of underserved population that live in poor and remote rural areas or in poor urban communities and refugee camps. At the same time, by involving service users in planning and management and by establishing mechanisms for monitoring (Target 6.b), the capacity of the state, responsiveness to citizens and legitimacy can be built even in contexts where such capacity has been eroded through protracted crises and conflict.