Calculate the first and last days first
Record when you expect to reach the accommodation and when you must leave it on the final day. Include station transfers, luggage and check-in. The departure time of your return train is not the moment sightseeing ends. A detour to collect stored bags can shorten the final day further.
Write down a realistic free period for each day. Arriving on Friday evening and returning on Sunday morning creates a different visit from Friday lunchtime to Sunday evening, although both involve two nights. Do not count the edge periods as full sightseeing days. Consider what activities actually fit into them once the necessary travel tasks are included.
Evaluate the additional night specifically
Compare another night's accommodation with what it enables. It may create a whole extra day, or simply a calmer departure morning. Both can be valuable, but they are different benefits. Include extra meals and any changed outward or return transport rather than adding only the room rate to your budget.
A longer stay may help when important attractions open on different days or you want a slower pace. It is less compelling if you would fill the extra day with arbitrary activities simply because it exists. Decide what matters at the destination first, then examine which duration gives those interests appropriate room.
With a limited budget, changing the transport may be another option. An earlier arrival or later return can create time without another hotel night, but may involve a very early start or a tiring journey home. Assess the demands of the complete trip rather than counting only the additional hours spent at the destination.
Do not allocate every available minute
Leave room in the calculation for meals, finding your way and breaks. Available hours cannot all be converted into admissions and walking. One substantial museum visit may make a satisfying day even when the schedule appears to contain spare time. Short trips in particular benefit from a few clear priorities rather than a fully occupied spreadsheet.
Finally, compare two understandable versions and describe their difference in one sentence: perhaps one additional full day, or a later departure without rushing. The third night then becomes a reasoned choice. The number of nights on its own says less than the particular sequence of activities and rest that you want those nights to make possible.
