National Electrical Code 110.16 Arc-Flash Hazard Warning requires the date to be on the arc flash label.
NFPA 70E 130.5(H) does not require the date to be listed on the label. However it does require the study data shall be reviewed for accuracy at intervals not to exceed 5 years.

The question:
Does your company/clients list the date on the arc flash label
Yes
No
It depends

Its kind of hard to ensure the 5 years is kept up to date if there is no good reference on the label (or some other method) ...

What other ways are people using to verify how long its been? beside labels or 1lines?

National Electrical Code 110.16 Arc-Flash Hazard Warning requires the date to be on the arc flash label.
NFPA 70E 130.5(H) does not require the date to be listed on the label. However it does require the study data shall be reviewed for accuracy at intervals not to exceed 5 years.

What this does not say is, "you need to update a arc flash label every 5 years"
We update the arc flash study during every change to the system. If a 3phase circuit changes, we update the arc flash study (and the label) immediately.

Thus we have met the "study accuracy" requirement as well as the arc flash update upon change requirement. We are always adding and removing so the update occurs at least yearly.