A preventive maintenance schedule is easy to write and hard to keep, and the gap between the two is where most maintenance improvement projects die. The schedule that gets written is a list of assets with dates. The schedule that holds is one that somebody costed in hours, staffed against the technicians actually available, and then watched for deferral rather than for completion. This page is about the second kind: how to build the interval list, how to check it can be carried, and what to look at monthly so that slippage is visible while it is still small.
Start from the manual, per asset, and write down why
The manufacturer's interval is the starting point and the only one you can defend on day one. Where you depart from it, write the reason on the asset: a pump on continuous duty in a dusty room is not the pump the manual assumed, and the next person needs to see that somebody thought about it.
Cost the schedule before you date it
On the worked example this site publishes, 180 assets at four tasks a year at 1.1 hours is 60 jobs and 66 technician hours a month, $3,168 at a $48 loaded rate. That number, checked against the people you have, is what tells you whether the schedule is a plan or a wish.
Float the dates from last completion
A fixed calendar drifts out of step the first time a job slips, and then every subsequent date is wrong in the same direction. Scheduling the next occurrence from when the last one was actually done keeps the interval real, which is the thing the schedule is trying to control.
Review deferral monthly, and act on the repeat offenders
The same five jobs deferred every month is not a scheduling problem, it is a message: either those assets need a different interval, or the schedule is over-committed. Both are fixable, and neither is visible on a completion percentage.
Questions people ask about preventive maintenance schedule
What is the difference between a PM schedule and a PM plan?
In practice, nothing; the words are used interchangeably. Where sites separate them, the plan is the decision about what each asset needs and the schedule is when it falls due.
How do we schedule usage-based tasks?
From a meter reading rather than a date, which means somebody has to collect the readings. If nobody is collecting them, a usage interval is a calendar interval in disguise and should be written as one.
Should statutory inspections be on the same schedule?
Yes, because they consume the same hours, but marked as statutory: their intervals are not yours to adjust and the evidence they require is different from a normal PM record.