Here is a good example of why ports matter. Here is the itinerary for the Tahitian Princess' 2009 World Cruise - too many sea days and no overnights in ports.

Quote

117 days departing January 14, 2009 on
Princess' Tahitian Princess


ITINERARY


DAY DATE PORT ARRIVE DEPART
Wed Jan 14 Fort Lauderdale, FL 5:00pm
Thu Jan 15 At Sea
Fri Jan 16 Grand Cayman, Cayman Islands 10:00am 6:00pm
Sat Jan 17 At Sea
Sun Jan 18 Panama Canal (Full Transit) (Cruising) 7:00am 4:30pm
Mon Jan 19 At Sea
Tue Jan 20 Manta, Ecuador 6:00am 7:00pm
Wed Jan 21 At Sea
Thu Jan 22 At Sea
Fri Jan 23 Lima (Callao), Peru 7:00am
Sat Jan 24 Lima (Callao), Peru 1:00pm
Sun Jan 25 At Sea
Mon Jan 26 At Sea
Tue Jan 27 At Sea
Wed Jan 28 At Sea
Thu Jan 29 Easter Island, Chilean dependency 9:00am 6:00pm
Fri Jan 30 At Sea
Sat Jan 31 At Sea
Sun Feb 1 Pitcairn Island, UK Territory 10:00am 2:00pm
Mon Feb 2 At Sea
Tue Feb 3 At Sea
Wed Feb 4 Papeete, Tahiti, French Polynesia 8:00am 5:00pm
Thu Feb 5 At Sea
Fri Feb 6 Rarotonga, Cook Islands 8:00am 5:00pm
Sat Feb 7 At Sea
Sun Feb 8 At Sea
Mon Feb 9 Crossing International Dateline 8:00am 8:00pm
Wed Feb 11 At Sea
Thu Feb 12 Auckland, New Zealand 7:00am 10:00pm
Fri Feb 13 At Sea
Sat Feb 14 At Sea
Sun Feb 15 At Sea
Mon Feb 16 At Sea
Tue Feb 17 Burnie, Tasmania, Australia 8:00am 6:00pm
Wed Feb 18 At Sea
Thu Feb 19 Sydney, Australia 7:00am 10:00pm
Fri Feb 20 At Sea
Sat Feb 21 Brisbane, Australia 8:00am 6:00pm
Sun Feb 22 At Sea
Mon Feb 23 At Sea
Tue Feb 24 Cairns, Australia 7:00am 6:00pm
Wed Feb 25 At Sea
Thu Feb 26 At Sea
Fri Feb 27 Rabaul, Papua New Guinea 7:00am 2:00pm
Sat Feb 28 At Sea
Sun Mar 1 At Sea
Mon Mar 2 Guam, U.S. Territory Noon 7:00pm
Tue Mar 3 At Sea
Wed Mar 4 At Sea
Thu Mar 5 At Sea
Fri Mar 6 Osaka, Japan 8:00am 8:00pm
Sat Mar 7 Hiroshima, Japan 9:00am 5:00pm
Sun Mar 8 At Sea
Mon Mar 9 Inchon, South Korea 8:00am 5:00pm
Tue Mar 10 At Sea
Wed Mar 11 Shanghai, China 7:00am 6:00pm
Thu Mar 12 At Sea
Fri Mar 13 At Sea
Sat Mar 14 Hong Kong, China 7:00am 8:00pm
Sun Mar 15 At Sea
Mon Mar 16 At Sea
Tue Mar 17 Ho Chi Minh City (Saigon), Vietnam 7:00am 7:00pm
Wed Mar 18 At Sea
Thu Mar 19 Sihanoukville, Cambodia 9:00am 6:00pm
Fri Mar 20 At Sea
Sat Mar 21 Bangkok, Thailand 7:00am 7:00pm
Sun Mar 22 At Sea
Mon Mar 23 At Sea
Tue Mar 24 Singapore 7:00am 5:00pm
Wed Mar 25 Kuala Lumpur (Port Kelang), Malaysia 7:00am 6:00pm
Thu Mar 26 At Sea
Fri Mar 27 Port Blair, Andaman Islands, India Noon 7:00pm
Sat Mar 28 At Sea
Sun Mar 29 At Sea
Mon Mar 30 At Sea
Tue Mar 31 At Sea
Wed Apr 1 Bombay (Mumbai), India 7:00am 10:00pm
Thu Apr 2 At Sea
Fri Apr 3 At Sea
Sat Apr 4 At Sea
Sun Apr 5 Dubai, United Arab Emirates 7:00am 8:00pm
Mon Apr 6 At Sea
Tue Apr 7 At Sea
Wed Apr 8 Salalah, Oman 7:00am 5:00pm
Thu Apr 9 At Sea
Fri Apr 10 At Sea
Sat Apr 11 At Sea
Sun Apr 12 At Sea
Mon Apr 13 Luxor (Safaga), Egypt 6:00am 10:00pm
Tue Apr 14 At Sea
Wed Apr 15 Suez Canal, Egypt (Cruising) 1:00am 5:00pm
Thu Apr 16 Port Said, Egypt 7:00am 8:00pm
Fri Apr 17 At Sea
Sat Apr 18 Athens (Piraeus), Greece 9:00am 6:00pm
Sun Apr 19 At Sea
Mon Apr 20 Sorrento, Italy 8:00am 6:00pm
Tue Apr 21 Rome (Civitavecchia), Italy 7:00am 6:30pm
Wed Apr 22 Cannes, France 9:00am 6:00pm
Thu Apr 23 Barcelona, Spain 11:00pm
Fri Apr 24 At Sea
Sat Apr 25 Gibraltar, UK Territory 7:00am 1:00pm
Sun Apr 26 Lisbon, Portugal 10:00am 6:00pm
Mon Apr 27 At Sea
Tue Apr 28 At Sea
Wed Apr 29 Cork (Cobh), Ireland 8:00am 6:00pm
Thu Apr 30 At Sea
Fri May 1 Paris (Le Havre), France 7:00am 7:00pm
Sat May 2 London (Dover), England 7:00am 5:00pm
Sun May 3 Paris (Le Havre), France 7:00am 6:30pm
Mon May 4 Zeebrugge, Belgium 8:00am 6:00pm
Tue May 5 Amsterdam, Holland 9:00am 5:00pm
Wed May 6 At Sea
Thu May 7 Copenhagen, Denmark 7:00am 5:00pm
Fri May 8 At Sea
Sat May 9 Helsinki, Finland 8:00am 5:00pm
Sun May 10 St. Petersburg, Russia 7:00am 9:00pm
Mon May 11 Tallinn, Estonia 9:00am 3:00pm
Tue May 12 Stockholm, Sweden 7:00am