Hello, I have a few brushed-motor 12kg Servos, brand-new the idle current is ~5mA. However after some use, the idle current increase quite a lot to about 30-40mA.
The affected Servos still work although the min and max angle seems to be slightly off by a few degrees, and under load the current also seems to have increased from about 0.8A peak previously, and after some use, now about 1.3A peak. The Servo is rated to 1A. It still works even under load, and there is no weird noise, just the current increase. I wouldn't be surprised if it did fail at some point, but then I will do a tear-down. What would cause a current increase in a brushed motor, could be the gear-box binding and increasing the load, but then the idle current has increased, or could be the motor brushes or a partial short in the windings / rotor commutator.
There is a 16kg brushless alternative but the cost 3x the price of the brushed motor.
Thanks, any advice welcomed.

I would say still a small force/load on the shaft of the servo making the servo to work to hold its position..

Could be slop in the gears as they wear causing the servo motor to have to hunt for neutral a bit more aggressively, or there's increased friction due to wear or dirt or lack of lubricant. Or maybe the magnet has weakened over time.

You mentioned it's a brushed motor. The brushes will wear out and become less efficient.

Check if the position sensor/pots are clean and mounted correctly, sounds like they have an issue holding the correct position as well...

remove the mechanism from the servo. does the current go down?
program a center point different than the one you have now. does the current go down?