Contemporary advice about building habits reproduces devices that monastic rules formalised long before. The parallels are close enough to be worth setting out, and so is the difference.
Fixed times replace decisions
Monastic timetables assign each activity an hour, so that beginning does not depend on inclination and the question of whether to start is never posed.
Modern habit advice arrives at the same device, recommending that an activity be attached to a fixed time or an existing routine rather than left to intention.
The reasoning is identical in both cases, which is that motivation fluctuates while a schedule does not, and the schedule is what carries the practice through low periods.
The environment is arranged in advance
Rules specify where activities occur, what is kept in each space and what is removed, which reduces the number of choices available in any given room.
The contemporary equivalent is designing surroundings so that a desired action is easy and an undesired one requires effort, which is the same principle stated in different vocabulary.
Both approaches treat willpower as unreliable and arrange conditions so that less of it is needed, rather than trying to strengthen it directly.
Small units are repeated rather than large ones attempted
Monastic observance is built from short repeated offices spread through the day rather than from occasional intense efforts, and the rules are explicit about consistency over intensity.
Habit literature makes the same recommendation, advising very small daily actions on the grounds that a practice too demanding to sustain will stop entirely.
Both traditions of advice also treat interruption as normal and provide for resumption without penalty, since a rule that punishes lapses tends to be abandoned after one.
Accountability is external
Communities supply observation, since living with others who keep the same schedule makes departures visible without any formal enforcement.
Modern advice reaches for the same thing through partners, groups and public commitments, which reproduce visibility for people who live alone.
In both cases the mechanism is social rather than moral, and it works by making the practice something other people notice rather than something only the practitioner knows about.
The purposes are not the same
Monastic rules organise a life around an end the community holds in common, and the schedule is subordinate to that end rather than valuable in itself.
Habit advice usually leaves the end to the individual, offering a method that can be applied to any goal, which makes it portable and also leaves the harder question open.
The techniques transfer cleanly because they are structural, but a method for doing things consistently does not answer which things are worth doing.