I recently pulled off my alternator to replace the thermostat and decided to do the brushes in the alternator. This was the wear on the brushes that I pulled after ~165k miles. I am assuming the alternator was original, as well as the water pump, since I bought the car at ~110k miles. Decided to leave the pump alone but am curious as to how long these pumps typically last. I am sure there is quite a bit of variation but life expectancy could have some merit even for external water pumps. There is definitely more merit to preventative maintenance on internal water pumps since they are usually changed during TB replacement. Debating about replacing it since I only have a short window to replace myself otherwise will have to pay a premium to have mechanic replace the pump in the future.