Yeah it varies from one airport to another. It can also depends on layover time. In Hong Kong (on my way from Aus to Vietnam) I had to leave through customs to get to another part of the airport and enter through customs to get my connection. I was fingerprinted and facemapped both ways.

Similar happened when connecting in Kuala Lumpur where the layover was 9 hours due to typhoon and the airline forced me to leave the airport, allegedly infringed to go to a hotel, but I doubled back and snuck into a closed off area where someone forgot to lock out an elevator to sleep for a bit. They force you to leave the airport so there are fewer people just milling about for hours.