Hydraulic reciprocating seals have been widely used to prevent fluid leakage and to provide lubricant film on counter surface in various hydraulic system. The degradation of the seal may cause the catastrophic failure of the hydraulic system. To assess the durability of the seals and the compatibility with counter surface, accelerated life testing (ALT) has been typically employed from industry. However, ALT often takes up to a few months to cause a failure of the seals, and therefore, there is a need to develop more efficient ALT methods. In this work, the degradation characteristics of polyurethane (PU) seals from field test are investigated and they are compared to those from the component and bench tests, with an aim to contribute to the development of ALT method. From the comparison of the cross-sectional profiles of the sealing surface of the PU specimens before and after the tests, both wear and compression set are found to be responsible for degradation of the PU seals. It is also shown that the major wear mechanisms of the PU seals from the field is abrasive wear and formation of pits. The component and bench tests performed in this work are shown to reproduce such wear mechanisms, and therefore, those test methods can be used as an ALT method for PU seals. In particular, the bench test proposed in this work may be effectively utilized to assess the durability and the compatibility of the seals with the counter surface. The results of this work are expected to aid in the design of ALT for PU seal.