Mi (2002) recently considered a two-dimensional optimization problem for the optimal age-replacement policy and the optimal work size. In order to find (y
∗,T
∗), Mi (2002) found the optimal age-replacement policy T
∗(y) for each fixed work size y, and then searched for the optimal work size y
∗. When applying this approach, for each fixed work size y, Mi (2002) obtained the bounds for T
∗(y). However, no bound for the optimal work size y
∗ was derived. In this note, the results on the upper bound for the optimal work size y
∗ are given.
