With SQ, you can check in to Changi up to 72hrs before your flight departs.
I may very well try this, to save on accommodation costs next month. However, with my luggage already checked through so I don't have to worry about it, and with my boarding pass already in hand (can't go airside without it), am I right in saying I can leave the airport through immigration any time I want and then return to the airport to sleep each night (in the snooze zone loungers)?
This means I could get 2 full days in Singapore doing some tourism, and not have to pay anything for accommodation costs. I love being in airports anyway, especially Changi, so it does not bother me.