The Ops infrastructure is all time-synchronized using a fully redundant NTP service that is provided and maintained by our infrastructure host.
All times in the software come from the Ops database to ensure they are accurate and from a single source; such as the timestamps for alarms and auditing. The time on the user's computer (the "client") is never used. This ensures that if it has the wrong time, it will not cause any issues.
As noted above, in no circumstances does Ops software ever rely on the time shown on client computers.
Regardless we do recommend that your clients are kept synchronized with an NTP server just to aid with visual comparisons where, for example, a user might compare the timestamp of an alarm inside Ops to their computer clock to see "how long ago did this happen?". Most computers and mobile devices automatically sync their time but for those that don't we recommend that you use the public ntp.org server pool which matches the time used by the Ops infrastructure.