A mill’ steel liner wear rate and total useful operating life is a function of its hardness (mostly).  Here is a chart displaying Liner Hardness on the Brinell Scale as a function of the tonnage of ore/rock milled/processed.

Not showed here is the impact a mill’s RPM has on the liner’s wear rate.

Comminution and Energy Consumption: By National Research Council (U.S.). Committee on Comminution and Energy Consumption