Crawler motors are not stressed anything like a race motor. The crawler motor last forever. Maybe get a set of spare brushes.
I have a Holmes 35.
AE FT B44.2, SC10, T4, B4.2, B4, 18T, 18R, TC4, L3.5O ** Losi MRC Pro ** CRC Carpet Knife ** Axial XR10, AX10, SCX10 ** Traxxas EMaxx ** JR Z1