The one question that sorts everything
Does it come back? A bundle of shingles does not come back. A nail gun does. That single question sorts almost every physical thing a service business owns, and it is the reason two different records exist rather than one big list of stuff.
Things that do not come back are counted in quantity, drawn down when consumed, and become job cost. Things that do come back are counted in units of one, tracked by who has them, and become an asset with a life and a maintenance history.
Materials: consumed, quantified, costed
Materials are the inputs the work turns into a finished result — fasteners, membrane, wire, fittings, filters, sealant. They live at a location with a quantity, they are received against a purchase order at a real cost, and they leave inventory permanently when a job consumes them.
Their defining behaviour is drawdown. Every material transaction moves the number in one direction or the other, and the sum of those movements has to equal what is on the shelf. That is why a material with no location is meaningless: you cannot draw down from nowhere.
Tools: the awkward middle
Tools are returnable but usually not individually valuable enough to justify a per-unit record — hand tools, extension cords, ladders, tarps. Many businesses track them as a quantity at a location and accept some shrinkage as a cost of doing business.
The moment a tool becomes expensive enough that its disappearance would be noticed and investigated, it should be promoted to equipment and given a unit record. There is no universal dollar threshold; there is only the threshold at which you would want to know who had it last.
Equipment: identified, custodied, maintained
- It exists as one unit with an identifier, not as a quantity.
- It has a status: available, in use, checked out, in maintenance, in repair, damaged, lost, retired.
- It has a condition, distinct from its status — a machine can be available and still be in poor condition.
- It has a holder: a person, a crew, a vehicle, or a job site.
- It accumulates a service and repair history that outlives any single job.
Rented equipment is a fourth case
Equipment you rent behaves like equipment operationally — it has custody, a condition and a return obligation — but it behaves like a cost on a clock financially. The return date is the number that matters, because a forgotten rental bills quietly until somebody notices.
What goes wrong when the three are merged
The classic failure is treating a returnable item as consumed. The count says you own six drills; you own eleven, four of which are in trucks and one of which walked off in March. Nobody can reconcile that count, so eventually nobody runs it.
The mirror failure is treating consumables as assets. Every box of screws gets a record, the record maintenance cost exceeds the value of the screws, and the whole practice is abandoned within a quarter.