Monetary respondent incentives are a means to counteract the trend toward declining response rates. This article summarizes the results of a series of experiments conducted in the past decade in the German General Social Survey. We found that prepaid monetary incentives led to a higher increase in response than promised incentives. There was no evidence that either promised or prepaid incentives had a systematic effect on sample composition. The incentives helped to reduce fieldwork efforts. Thus, the costs of incentives can—at least partially—be offset by a reduction in the number of contact attempts required to achieve a certain number of completed interviews. Our findings are highly credible due to the replicative design of the experiments.