Bucharest, the Transylvania loop and a month in Cluj
Most first trips pair Bucharest with a drive or train ride north into Transylvania: Brașov and Bran, Sighișoara, Sibiu, and in summer the Transfăgărășan. For a week like that, the 5 GB for 30 days handles navigation, train times and photos; the 3 GB for 15 days is enough if you stay a few days in Bucharest or join a guided tour. Two weeks that also take in Maramureș or the painted monasteries of Bucovina call for 10 GB, mostly because of maps and music in the car.
Cluj-Napoca and Bucharest also draw remote workers for a month or longer. The 20 GB for 30 days covers a laptop on the phone's hotspot, which every pack includes, for email, calls and browsing. When the 30 days end, you buy a new pack; the eSIM has no number to keep, only data.