Originally Posted by
LapLap
Yep! And there are anomalies even within this fairly accurate generalisation that can trip up travellers - for instance after the N'EX that leaves Shinjuku at 8:03am, the next one departs at 9:40.
Absolutely right.
It boils down to the fact that the N'EX from Shinjuku to NRT is not so frequent. It is wise to check the timetable and make reservations in advance.
OTOH - If you do find yourself in Shinjuku station having just missed a N'EX and you see no more N'EX trains for an hour or more, it's not fatal. You can get on the Yamanote line to Nippori and jump on the Skyliner. (Or take Chuo line to Tokyo and get a N'EX from there). These options can work out as quick as the N'EX (which takes a very long route from Shinjuku to Tokyo before going on to Narita airport).