Originally Posted by
TRAVELSIG
When I fly economy without the expedited immigration I tend to leave 4 hours before flight time- so very similar to your estimates I think?
That sounds very early to me; the only time I've left that early was the once I got stuck on China Eastern and being a non-OW carrier, wasn't sure how bad their regular Y check-in lines would be (turned out to be bad.)
Then again, even though I'm always in Y, I can use the J check-in lines (as can an awful lot of us with status.) No fast-track line with that, but the exit passport controls have never been that bad, and seem better with the division of space with security upstairs before passport control.
Leaving 3 hours ahead seems fine from Lower Sukhumvit if you're not around a rush hour, sometimes only about 2 1/2 if I'm leaving at the crack of dawn for the 8AM-ish JAL departure. Sometime the check-in desks don't even open before the 3-hour mark...