You need three things tracked per job — labor hours, materials and a consistent overhead allocation. Everything else is refinement.
Monthly profit tells you whether the business worked. Job costing tells you which work worked. Owners who only see the monthly number end up subsidising a service line for years without knowing it.
The three things to track
Labor hours, at loaded cost — wage plus payroll tax plus insurance, not the hourly wage. Loaded cost is routinely 25–35% above the raw wage.
Materials, assigned to the job rather than dumped into a monthly supplies account.
Overhead, allocated consistently. Perfect allocation is not the goal; consistency is, because the comparison between jobs is what you are after.
Where owners get it wrong
The most common error is comparing jobs on revenue instead of gross margin. A $9,000 job at 12% margin is worse than a $2,500 job at 40%, and revenue-ranking hides that completely.
| Job | Revenue | Gross margin | Margin $ |
|---|---|---|---|
| Large install | $9,000 | 12% | $1,080 |
| Small service | $2,500 | 40% | $1,000 |
| Recurring maintenance | $1,800 | 52% | $936 |
Nearly identical contribution. Very different amounts of your life.
Review quarterly, not monthly
One month is too noisy. A quarter is enough to see whether a service line is genuinely underpriced or just had a bad run — and quarterly is a cadence you will actually keep.
Once you can see margin by line, pricing stops being a guess. That is usually the point at which owner pay becomes a solvable problem rather than a leftover.