Effective lifetime of LLIN sustained coverage, depending on pre-intervention EIR and coverage. Entomological inoculation rate (EIR) is defined by infectious bites per adult per annum (ibpapa). Coverage (%): light-blue lines and crosses = 40, magenta lines and crosses = 50, red lines and crosses = 60, blue lines and crosses = 70, green crosses = 80. Figures c & d EIR: yellow lines = 64, grey lines = 128, black lines = 256. Figures a & c) Effective lifetime on vertical axis, Figures b & d) Natural logarithm of effective lifetime on vertical axis. For comparison, the effective life of a mass distribution with 70% coverage and a half life of four years is plotted in a and b (thin dashed blue lines and crosses).