Because that’s how things become habitual. There is no shortcut.
When something becomes habitual it becomes ‘semi-automatic.’ And the only way things become semi-automatic is through repetition. Our experiences and psychology, as a scientific field, are very much aligned on this one. From typing, to writing, to walking, to driving, frequently repeated behaviors become second nature.
That’s what you want to happen with your new great habit. It’s hard to believe, but it will happen. Just like your first awkward steps as a toddler became your easy gait. Just as your mental lists for safe driving (“signal,” “check blind spot,” . . .) became routinized, so too will your new habit.
So, keep on going! Keep on going when you feel like it. Keep on going when you don’t. Just keep going!