One of the major cost components in tool economics is the cost incurred due to deviation in workpiece quality as a result of poor tool-cutting conditions. Commonly, the operating conditions of a culling tool may be restored via regrinding during periodic intervals of the tool's life. This paper proposes that optimal regrinding interval ought to be determined with respect to the optimal number of regrindings. The product of these two values defines the economic life of a tool. The objective function is the minimization of the sum of the expected costs of failure, regrinding, tool purchase, machining, and deviation in workpiece quality. The cost of deviation in workpiece quality is modelled using Tagucbi's loss function. The effect of cutting speed on tool regrinding interval is also explored.