The paper analyzes a profit-maximizing serial replacement problem under variable asset productivity, operating cost, and replacement cost that depend on asset age and installation time. The majority of modern asset replacement models minimize costs. The authors examine and highlight essential differences between profit-maximizing and cost-minimizing replacement strategies in the infinite-horizon framework. Next, they construct and analyze an effective multi-cycle replacement algorithm that approximates the infinite-horizon solution with non-equal asset lifetimes. Numeric simulation illustrates theoretic outcomes and demonstrates a good performance of the constructed algorithm under different patterns of changing technology.