People routinely report that a week of retreat moved their practice further than a year of daily sitting. The explanation is not that retreat practice is better but that the conditions differ in specific, describable ways.
Decisions are removed rather than reduced
A retreat schedule fixes when to wake, eat, sit, walk and sleep, and participants agree to it in advance rather than choosing each item as it arrives.
Deciding is effortful, and a day at home contains hundreds of small choices that each draw a little attention and leave a residue of deliberation behind them.
Handing that over to a timetable frees the capacity those decisions consumed, which is why the first day often feels oddly restful before any practice has done anything.
Continuity is the active ingredient
A daily sitting is bounded by everything before and after it, so attention arrives carrying the morning and leaves into the afternoon.
On retreat, one session ends and the next begins within an hour, with walking practice between, so the state built in one period is still partly present at the start of the next.
Practice that accumulates across a day rather than resetting each morning reaches depths that a single session simply does not have time to approach.
Input is deliberately impoverished
Silence, no reading, no devices and often no eye contact are standard, and each removes a channel through which novelty arrives.
Novelty is what attention is built to orient toward, so removing it lowers the competition for attention rather than requiring the meditator to resist more strongly.
The same reduction is why ordinary experiences become unusually vivid on retreat, since a mind with little to process gives considerable processing to very little.
Social performance drops away
Not speaking to others for several days removes the continuous background task of presenting a coherent self to people.
That task is largely invisible until it stops, and its absence accounts for a good deal of the strangeness participants describe around the third day.
It also removes the option of discharging difficulty through conversation, which is one reason material that daily life keeps at bay tends to surface.
Intensity carries its own risks
The same conditions that accelerate practice can destabilise people, and reports of anxiety, disorientation and intrusive memories on long retreats are well documented rather than rare curiosities.
Reputable centres screen applicants, provide teacher interviews during the retreat, and are willing to reduce a participant's practice hours or end their retreat early.
Anyone with a history of significant mental health difficulty is generally advised to discuss an intensive retreat with a clinician first, since the setting removes exactly the supports that ordinarily help.