The grind gets boring right before it starts working. Boredom is often the last checkpoint.

Boredom arrives at a specific point, after the novelty ends and before the results show up. That gap is where most people stop, not because it got hard but because it stopped being interesting. Nothing has gone wrong at that moment; you have reached the unglamorous middle, which is also where things start compounding. Interest is a poor signal for whether something is working.

Decide on a duration in advance so boredom cannot end things for you. Twelve weeks, a season, a semester. Make the routine dull and fixed so it needs no motivation to run.