Slow travel is often described as a mood, which makes it hard to act on. It is more usefully defined by a ratio: how much of a trip is spent in transit against how much is spent in one place.
Transitions carry the cost
Moving between bases means packing, checking out, travelling, checking in and re-orienting. That consumes most of a day regardless of how short the journey is.
Each transition also has an emissions cost, and short hops are the least efficient way to cover distance because departure and arrival dominate.
A two-week trip with six bases spends nearly half its days on the mechanics of moving.
Familiarity changes what a place offers
The first day anywhere is spent on orientation: where to eat, how transport works, which streets lead where.
That knowledge is discarded on departure. Staying longer lets it compound, and the third day at a base is more productive than the first day at a new one.
It also opens things that are unavailable to a passing visitor: a market that runs weekly, a class that meets twice, a walk that needs good weather.
Money lands differently
A traveller staying a week uses ordinary services rather than only visitor-facing ones, because the highlights run out quickly.
Longer bookings also favour independent accommodation, which is more likely to be locally owned than a chain sized for short stays.
The same total spend reaches a wider set of households, which is the mechanism behind most claims about tourism benefiting communities.
Ground transport becomes an option rather than a sacrifice
Trains, buses and ferries are usually lower-emission per passenger than short flights, but they cost hours.
Those hours are only affordable when the itinerary is not packed, so slow travel and low-carbon travel tend to arrive together rather than by coincidence.
Overland routes also make the geography legible, which changes how a traveller understands the distances involved.
It is not the same as being unplanned
Slow travel is sometimes confused with improvising, but fewer bases usually require more advance booking, not less.
Long stays and rail seats are the things that sell out, while a night in a passing town is generally available.
The planning shifts from scheduling each day to choosing fewer places well, which is a different task rather than an absence of one.