When you enter Singapore you fill out an arrival card when you are processed by inbound immigration. Part of that card is stapled into your passport and removed (by the immigration official) upon exit.Departure is very easy to find and there is an easy immigration departure point in each terminal. They are polite and very efficient. You go through outbound immigration and into the very best airport in the world - it is a destination in itself - with lots of shops, spas, a swimming pool, cinema, food of every type, gardens, waterfalls and competitions.Security is generally at each gate entrance (although I understand that this might be changed when Terminal 4 opens shortly).