That is to use the transit hotel of course to avoid an early morning schlepping shuffle.

I have a UA flight SIN-NRT at 0700 in the morning.
Can I check-in luggage and all landside at the UA counters the previous day/night?

I'm not sure if this gets a UA specific answer or a universal response of no check-in counters are available for specific flights until 3 hrs prior to flight or something.

Thanks.