In addition to carrying a spare set of brushes, consider having a second starter. If the one you have now is relatively new, pick up a working used one. Starters can be swapped out in a couple of minutes and you won’ miss a practice session or race. Replacing the brushes is going to take half an hour. External starters would be another option, but believe that’s overkill.
Not a big fan of using vice grips on the gear during reassembly as shown in the video. Be careful not to damage it.