Rotation processes are the primary priority of techniques and equipment for in-process tool wear assessment. The application of a persistent indirect method that makes use of a power monitor device to sense the total power needed to drive the machine tool's spindle motor is explained. This approach is based on experimental associations among wear and cutting power. Additionally, a method for calculating the real cutting power is created, which accounts for the power used by the spindle while it is inactive and its dependency on the machine tool's thermal condition. An implementation on the shop floor is demonstrated and described for a system that implements an automatic tool replacement strategy based on such indirect wear assessment. The integration of a closed-loop adaptive control targeted at maximizing metal removal rate while following tool life limits is also described in terms of future advances.