Technology scaling leads to the reliability issue as a primary concern in Networks-on-Chip (NoC) design. Due to routing algorithms, some routers may age much faster than others, which become a bottleneck for system lifetime. In this chapter, lifetime is modeled as a resource consumed over time. A metric lifetime budget is associated with each router, indicating the maximum allowed workload for current period. Since the heterogeneity in router lifetime reliability has strong correlation with the routing algorithm, we define a problem to optimize the lifetime by routing packets along the path with maximum lifetime budgets. A dynamic programming-based lifetime-aware routing algorithm is proposed to optimize the lifetime distribution of routers. The dynamic programming network approach is employed to solve this problem with linear complexity. The experimental results show that the lifetime-aware routing has around 20 %, 45 %, 55 % minimal MTTF improvement than XY routing, NoP routing, and Oddeven routing, respectively.