| Facility lease and lab space |
Fixed |
Use $6,500 per month in fixed overhead for the relevant planning range. |
Spreading rent across jobs and hiding true monthly burn. |
| Professional liability insurance |
Fixed |
Use $1,800 per month as fixed overhead from Month 1 through Month 60. |
Treating insurance as job-specific when it must be paid even in slow months. |
| First-year core staff payroll |
Fixed |
Use $590,000 per year for the CEO and Principal Engineer, Level III technician, two senior field technicians, technical sales manager, and operations coordinator. |
Calling underused technician payroll variable just because labor is tied to service delivery. |
| Consumables and couplants |
Variable |
Model at 8.5% of revenue in the first year, stepping down to 6.5% by the fifth year. |
Using a flat dollar budget instead of linking spend to billable work. |
| Field travel and lodging |
Variable |
Model at 12.0% of revenue in the first year, declining to 10.0% by the fifth year. |
Treating remote-job travel as harmless overhead instead of margin drag. |
| Equipment maintenance and calibration |
Variable |
Model at 5.5% of revenue in the first year, declining to 3.5% by the fifth year. |
Ignoring repair spikes until they hit cash flow after heavy field use. |
| Technician hiring and vehicle additions |
Semi-fixed |
Add capacity in steps when volume forces more field coverage, vehicles, or lab throughput. |
Assuming margins improve smoothly when the next hire or vehicle creates a step-up. |