It typically takes two to get the third stage up there, and only the third stage stays in orbit. Alternative shuttle designs, BFR and New Glenn start at two but

It typically takes two to get the third stage up there, and only the third stage stays in orbit. Alternative shuttle designs, BFR and New Glenn start at two but you wouldn't want to carry around all that extra weight on a second stage unless you had a very specific mission set (launch the ISS in a couple of missions or have a stage that goes and lands on Mars). Not optimized for typical payloads.