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 constantly; alerts track change from that baseline. ISO zones serve only as an initial reference at installation, not as long-term thresholds. DHMSCare judges every machine against its own baseline, so even old machines are monitored accurately.