An old machine has always vibrated a lot. Will a monitoring system alarm on it all the time, and how should thresholds be set?

No. DHMSCare learns a baseline for each machine, so an old machine that vibrates steadily at its own level does not alarm all the time. Alerts follow changes from that baseline. ISO zones serve only as a first reference at installation, not as long-term thresholds. DHMSCare judges every machine against its own baseline, so even old machines are monitored accurately.