I have a pair of HGST HDN728080ALE604 drives (8TB Deskstar NAS). One has SMART 22 at 100 after 43,239 power-on hours; the other is offsite and online, but is the same age and had SMART 22 at 100 last time I checked.

My other helium drives (WUH721816AL5204 — 16TB Ultrastar DC HC550) are SAS, and I don't know how to check helium levels of these (smartctl reports neither SMART 22 nor anything related to helium).