In today’s competitive landscape, employees increasingly negotiate idiosyncratic deals (i-deals), referring to personalized work arrangements that address recipients’ unique work needs and preferences. While i-deals unfold in a dyadic context between subordinates and their managers, the consequences of i-deals concern everyone including co-workers and the organization. Focusing on task and development i-deals, we propose a trickle-down model to explore whether and how organizations benefit from i-deals. First, we argue that managers’ task and development i-deals cascade down to their subordinates, leading them to have similar i-deals with downstream consequences for co-workers and the organization. Furthermore, we propose that effective implementation of task and development i-deals are context-specific: we integrate the role of managers’ servant leadership as a boundary condition to explore the association between managers’ and subordinates’ task and development i-deals. We also integrate subordinates’ prosocial motives to explore the association between subordinates’ task and development i-deals and their work outcomes. We draw on work adjustment, social learning and social information processing theories to study our proposed associations. The results of a matched employee–manager dataset collected in the Philippines support our hypothesized model. This study contributes to i-deals research by: (1) testing whether and how task and development i-deals can be mutually beneficial for all the involved parties; and (2) revealing how the context, at the individual level, explains how and when task and development i-deals can best be implemented in workplaces. This study highlights that individualization of HR practices need not be a zero-sum game.