The question arises before every trip, and the default answer – ‘3 days is good’ – is meaningless. Three days is enough for Valencia, just right for Lisbon, and ridiculously short for Rome. The duration doesn’t depend on a universal rule, but on three interconnected factors.

The Actual Size of the Historic Center

Not the size of the entire city – its population has almost no bearing on visit time. What matters is the area of the center where the points of interest are concentrated. A city like Valencia or Prague has a compact center, walkable in a day. Rome or Paris spread their must-sees across several distinct neighborhoods, each deserving half a day on its own.

A quick way to estimate: count the number of distinct neighborhoods or zones that contain at least one major site. One neighborhood = half a day if you want to see things without rushing.

The Number of Sites Requiring Timed Reservations

Museums and monuments with high visitor numbers (Louvre, Vatican, Sagrada Família, Alhambra) often require a pre-booked time slot. Each of these sites structures a full half-day around itself – it’s impossible to follow it immediately with another dense activity, unless you’re running. The more sites of this type a city has, the more days it demands, regardless of its geographical size.

The Pace You Actually Want to Maintain

This is the most often ignored factor. An itinerary designed for an intensive pace (two to three major activities per day) can cover a city in two fewer days than a relaxed-pace itinerary. Neither is the ‘right’ choice in absolute terms – but choosing consciously before setting the length of stay avoids the most common mistake: booking too few days for the pace you actually wanted to follow, then ending up exhausted halfway through.

A Rule of Thumb

For a medium-sized European city with 2-3 sites requiring mandatory reservations: plan for a minimum of 3 days at a normal pace, 4 if you want to keep free time each day. For a dense historical capital (Rome, Istanbul, Cairo): it’s hard to go below 4 days without sacrificing an entire neighborhood. For a compact city focused on beaches or strolls (Valencia, Nice): 3 days are more than enough; a 4th day is mainly for slowing down rather than seeing more.

The real pitfall isn’t miscalculating – it’s setting the length of stay before even listing what you want to see, then forcing everything into it.