FairTax4me

Well the amount of runs you can get out of a motor before it needs to be rebuilt is dependent on how you treat it and what type of motor it is. Generally motors with lower turns will need to be rebuilt more often because they run at higher RPMs. Higher RPM looks good on paper, but when you get it in your truck you'll usually find that it doesn't have much torque on takeoff, and it runs too hot which scorches the comm and brushes and only accelerates wear and tear on the motor. That severely limits the amount of flexibility you have with gearing and battery types, since lower turn motors are usually not designed for packs with over 6 cells.

Higher turn motors create more torque on takeoff, and can usually safely run packs with more than 6 cells because they don't run as hot. You also have a ton more flexibility with gearing because of that. Also since it doesn't run as hot, the brushes are less likely to get scorched, which keeps them soft and prevents them from wearing down the comm. (the comm is the part of the motor where the brushes make contact with the motor shaft).

Another thing that comes into play with that motor I linked, is endbell timing. Basically what that is is the angle of the endbell (part that holds the brushes) compared to the magnets inside the motor. By advancing the timing, or increasing the angle, it lets the motor turn faster because it changes the point where the electricity is transferred from the brush to the armature during the revolution of the motor. Increasing the timing advance does also increase how hot the motor runs, but that can be fixed by proper gearing. That motor in particular should be fine with the stock gearing in the truck.

Any brushed motor will eventually need to be rebuilt, but if you keep the motor temperature down, and spray it out with compressed air after each run then it should last at least 20 - 40 runs.