Pulsed inputs of resource subsidies have profound consequences on population and community dynamics. Motivated by field examples from Bahamian islands and other systems, I explore theoretically the consequences of temporally-dynamic inputs of resource subsidies. Mathematical models show that two aspects of temporal heterogeneity, timescale and timing, are fundamentally important to understand outcomes of pulsed resource subsidies. Timescales of subsidy inputs determine whether behavioral, demographic, or evolutionary mechanisms of consumers respond to pulsed resources, and affect subsidy effects on consumer demography and community dynamics. Timing of subsidy inputs affects whether temporal heterogeneity of subsidy inputs increases or decreases consumer fitness. What timing of resource pulses augments or reduces consumer fitness may depend on what fitness component (e.g., foraging traits, time to maturation, or energy reserve) is altered by a resource pulse. Furthermore, timing of subsidy inputs can determine whether resource subsidies stabilize or destabilize community dynamics. Scaling up the effect of pulsed resources from individual to population, community, and ecosystem levels may provide a great opportunity to advance ecological theories.