Comparing preventive and predictive maintenance as a pair leaves out the third option every site is already running, usually without admitting it: reactive maintenance, which is fixing things after they break. Including it changes the comparison, because a large share of any asset list genuinely belongs there and pretending otherwise produces plans that cover everything badly. This page puts all three side by side and says where each one is the correct answer rather than a failure of the others.
Reactive is a real strategy when it is chosen
A cheap item, a spare on the shelf, no safety consequence and nothing downstream stops: waiting for it to fail is the cheapest correct answer. What makes it a strategy rather than an oversight is that somebody decided it, wrote it down, and confirmed the spare exists. An asset that is reactive by accident has neither the decision nor the spare, which is where the cost actually appears.
Preventive is for wear you can anticipate
Where deterioration accumulates with time, use or distance, an interval catches it before it becomes a failure. It covers most of what a building, a fleet or a plant contains, needs no instrumentation, and its cost is hours rather than capital. Its limit is that it is blind between visits, which matters more the more expensive a failure is.
Predictive is for expensive failures that announce themselves
Where a failure would be costly and where it gives measurable warning, watching the condition beats a fixed clock. It is the most expensive to establish per asset, which is why it belongs on a short list rather than a whole site, and it needs a route from a reading to a scheduled job or it produces nothing but a dashboard.
Questions people ask about difference between preventive maintenance and predictive maintenance
What proportion of assets belongs in each?
There is no universal split and imported ones assume somebody else's site. Allocate by consequence and by whether the failure gives warning, then read your own results rather than a benchmark.
Is reactive maintenance ever wrong to choose?
When the asset has a safety or production consequence, or when nobody has confirmed a spare is available. Those two checks are what separate a decision from an omission.
How often should the allocation be reviewed?
Annually, and after any change to what the site does. Assets move between categories when what depends on them changes, and nothing about the asset itself announces it.