Two days covers the Acropolis and one museum if you pre-book. Three days is the comfortable minimum for the Agora without treating the metro as the holiday.
2 days: landmarks only
Day one: Acropolis in the morning, Plaka lanes, rooftop dusk. Day two: Acropolis Museum, Monastiraki lunch, ancient Agora if energy remains. Skip Delphi.
3 days: city plus neighbourhood
Keep the two-day core, then give day three to Koukaki or a slower Plaka morning with no major ticket — or Cape Sounion if you want the sea. This is the version that still feels like Athens rather than a queue.
5 days: Athens and Delphi
Three city days, one Delphi weekday (early start, sanctuary, museum), and one buffer for heat or a second ruin. Stay in Plaka, Monastiraki, or Koukaki so you are not commuting into the centre each morning.
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