Don't know about Hilti, but for most brands you can buy a complete new tool for a few more dollars than the rotor/armature price. Usually most expensive replacement part of a tool.
I know that.
Can you find out how much a complete cutter cost. A brand new cutter. I like to compare the price of a brand new cutter to tht of a rotor.
As some one said above, it is better to buy a new cutter than a rotor.