Start with consequence, not equipment
The usual approach is to list equipment and assign everything the same interval. That is administratively tidy and technically wrong. A bake oven and an ultra-low freezer holding a decade of irreplaceable samples do not carry the same consequence of failure, and should not receive the same attention.
Rank every asset by what happens if it fails on a Friday night. Anything where the answer involves losing something that cannot be replaced belongs at the top, regardless of how new it is.
Then account for duty cycle
Two identical freezers in the same room can wear at very different rates. The one opened forty times a day works dramatically harder than the one opened twice a week. Door openings, ambient room temperature and how full the chamber is all change the real load on the refrigeration system.
A unit in a hot room with heavy traffic warrants more frequent service than its twin in a cool room, even though the asset register says they are the same.
Add age and history
Equipment failure follows a curve. Very new equipment occasionally fails from installation or manufacturing issues, then settles into a long reliable period, then failure rate climbs again as components reach end of life. A twelve-year-old ultra-low freezer needs more attention than a four-year-old one.
History matters as much as age. A unit that has already needed two compressor-related repairs is telling you something about the next twelve months.
A workable starting framework
As a starting point — adjusted for your actual risk profile and whatever your quality system requires:
- Quarterly — ultra-low storage holding irreplaceable material, blood bank refrigeration, and any asset where failure is unrecoverable.
- Semi-annual — most ultra-low freezers, CO₂ incubators, growth chambers running continuous trials, and refrigerated equipment under heavy duty.
- Annual — lower-consequence equipment, lightly used units, ovens and general laboratory refrigeration.
Put calibration on the same calendar
Calibration and maintenance are routinely scheduled separately, which doubles the disruption and doubles the coordination. Combining them means one visit, one set of paperwork and one interruption — which is why calibration is included rather than added on in our Standard and Assured plans.
Make the record survive staff turnover
The most common failure of a maintenance programme is not technical. It is that the person who held the schedule in their head left. A schedule that lives with your service provider, with confirmation ahead of each visit and documentation after it, survives that.
