List the move from room to room
Include checkout, travel to the departure point, the main journey, arrival transport and access to the next room. Add luggage storage if check-in is later. A two-hour train does not necessarily mean only two hours of the day are used.
There may also be a meal bought during the transfer, a luggage fee or another reservation charge. Count only costs created by the move, and avoid adding meals twice if they already sit in the daily budget.
A hypothetical extra-city calculation
Imagine two travelers considering two nights in City B instead of staying in City A. Their intercity tickets would total $120, local station transfers $30 and luggage storage $16. The replacement accommodation costs $80 more than the nights they would otherwise keep. The move therefore adds $246 before any different activities or food choices.
If the new city also requires a separate airport transfer costing $40 more than the original plan, the additional total becomes $286. These are invented figures intended to show the categories, not real prices for a destination. The comparison subtracts the lodging already planned rather than incorrectly counting all of City B's room cost as extra.
Now consider the time. If packing and the room-to-room journey use much of one day, two nights may leave only one full day in City B. That can be worthwhile for a place you strongly want to visit, but it is a different proposition from imagining two additional complete sightseeing days.
Look at what the second city adds
A distinct landscape, a personal interest or a useful onward route can justify the move. Adding another city merely because it is nearby on a map may create more logistics than variety. Ask what you would do there that you would not otherwise experience.
Compare an overnight stay with a day trip, but do not assume the day trip is cheaper once repeated transfers and late returns are included. A second base can be the more relaxed option when it removes several long journeys.
Read the booking chain
Two accommodations and an intercity ticket create additional cancellation terms and arrival deadlines. Check whether changing one booking would leave the others unusable. A separate-ticket connection needs its own assessment rather than being treated as a continuous protected journey.
Keep the final departure in view. An open-jaw itinerary may avoid returning to the first city, but compare the actual fare and airport access. Do not add a backtracking journey merely because the original arrival airport feels familiar.
Give the new place enough room
If you add City B, remove some expectations from City A rather than trying to preserve every original activity. Leave the transfer day lightly scheduled and confirm where bags can go.
The right number of cities is the number that leaves time for the experiences you care about. A fuller map is not automatically a fuller trip; sometimes the strongest addition is another unhurried day where you already are.
