A practical checklist

  1. Record the maintenance type and actual date normally.
  2. Leave the optional hours value unspecified when it was not observed.
  3. Use notes to identify the missing reading and any source you may check later.
Illustrative recordA worked example

Service · September 23. Notes: “Filter replaced; hour reading not taken while machine was in workshop. Work confirmed from technician’s dated note.” The entry remains useful without an invented meter value.

What to avoid

Do not copy the last known meter value into a later entry as if it was newly read. That can make the machine appear to have accumulated no operating time.

All maintenance guides