This all depends on the kind of piercing in question. Some piercings call for straight studs to heal in, some call for rings, and some call for curved barbells. At your appointment/experience here we will by default always start with what is the recommended and most conducive to healing.
Why? Regardless of how good the piercing is, how high quality the jewelry is, etc. starting off a piercing on the “wrong foot” with a style that is not conducive to it healing will inevitably make healing an uphill battle.
We do support the idea of “informed consent” meaning that if our clients choose to get pierced with a piece, we don’t recommend starting with we will likely find a safe way to do so, but only after we explain our recommendations/hesitations with said piece. We do recommend coming in with a “final goal” and allotting some flexibility, things that factor in are, your individual anatomy, piercing healing tendencies (if said piercing does best initially with x gauge, or a stud instead of a ring), etc.