Fleet managers in the 10-to-50-truck range almost always face this question eventually: at what point does it make sense to hire a technician and build out a shop, versus continuing to outsource maintenance to a mobile or fixed-location vendor? The answer is almost never as clean as the payroll-versus-invoice comparison makes it look, because the true cost of each model includes a lot of line items that don't show up in the obvious calculation.
Here is how we think through the economics from both sides, and why most fleets in this size range end up running some version of a hybrid.
The True Cost of an In-House Technician
The starting point for most fleet managers is the technician's hourly rate or annual salary. That number understates the actual cost by a significant margin once you account for:
- Benefits and payroll burden. Health insurance, employer FICA, workers' compensation, unemployment, and any retirement contribution typically add 25–35% to base wages. A technician at $28/hour costs the fleet $35–38/hour in fully-loaded labor.
- Tools and equipment. A medium-duty diesel technician brings personal hand tools, but the shop needs to provide specialty tooling: scan tools with current software subscriptions, hydraulic jacks and jack stands rated for the equipment, press equipment, and the various manufacturer-specific adapters required for emissions system work. The upfront investment is real and the annual software subscription cost on diagnostic tooling is often underestimated.
- Bay space. Shop floor space in North Texas industrial areas carries a rent cost, and a bay sized for a Class 6 chassis needs ceiling clearance and floor rating appropriate for the vehicle weight. Heating and cooling a shop is not free. Bay overhead including lease, utilities, and insurance typically runs $18,000–$30,000 per bay per year depending on location and configuration.
- Parts inventory. An in-house shop that can execute same-day repairs on a diverse fleet needs a parts inventory. Carrying inventory ties up capital and creates obsolescence risk when fleet composition changes. Inventory management also requires discipline — parts that walk out without being charged to a work order are invisible losses.
- After-hours coverage. An in-house technician on a 40-hour week is not available at 11 PM when a truck breaks down on a job. After-hours breakdowns either wait until morning or require either overtime pay or an on-call structure.
- Training and certifications. FMCSA annual inspection authority requires certified inspectors. ASE certification requires testing and continuing education. Keeping a technician current on evolving emissions diagnostics — which change with every model year — requires funded training time.
When you add all of this up, a single fully-loaded in-house technician in this region costs a fleet somewhere in the range of $90,000–$130,000 per year before you account for capital investments in tooling and bay infrastructure.
The True Cost of Mobile or Outsourced Service
Mobile service invoices look expensive on a line-item basis. A service call that includes a travel charge, a diagnostic fee, and a labor rate at $120–$150/hour for two hours of work can run $350–$500 before parts. Multiply that by the maintenance cycle on a 20-truck fleet and the annual invoice total looks like a strong argument for going in-house.
But the outsourced model carries costs that are invisible, and it also offloads costs that an in-house model puts back on the fleet:
- No idle capacity cost. An in-house technician who doesn't have enough work to fill 40 hours is still being paid. A mobile service provider is only on the clock when needed.
- No training cost. The service provider bears the cost of keeping technicians current on new models, emissions systems, and software tools.
- No inventory carrying cost. The service provider stocks parts. The fleet pays parts cost on invoices but doesn't carry the capital or the shrinkage risk.
- After-hours availability. Many mobile service providers offer after-hours emergency response at a premium rate, which is often cheaper than a structured on-call arrangement with an in-house employee.
- Expertise breadth. A single in-house technician is limited by their own experience. A service provider handles diverse fleets across multiple customers, which typically means broader diagnostic exposure.
The real cost comparison is not technician salary versus monthly invoice total. It is the fully-loaded internal cost per repair event versus the fully-loaded external cost per repair event, multiplied by actual event frequency.
Where Each Model Breaks Even
The math generally favors in-house once a fleet can keep a technician productively utilized 80% of the time or better on scheduled and unscheduled maintenance. For most medium-duty fleets, that threshold falls somewhere around 35–50 trucks depending on equipment age, duty cycle, and PM interval discipline.
Below that threshold, the partially-utilized in-house technician is an expensive asset. The idle time cost is real — you are paying wages for hours that generate no maintenance output.
Above that threshold, the mobile vendor's travel charges and per-call overhead start to look expensive compared to an in-house technician who can walk across the yard to handle the same task.
There are also task-type considerations that cut across fleet size:
- Routine PM tasks (oil changes, filter swaps, tire rotations, fluid checks) are high-volume, low-skill, and highly repetitive. They are natural candidates for in-house execution even on smaller fleets, because a lower-paid lube technician or fleet coordinator can execute them without requiring a full diesel technician's expertise.
- Diagnostic and emissions system work requires current tooling, software, and training. Unless an in-house technician is actively kept current, complex fault codes are better handled by a provider whose entire business depends on staying current.
- DOT annual inspections require a certified inspector. If an in-house technician is not certified, inspections are outsourced regardless of fleet size.
The Hybrid That Works Best in the 10-to-50-Truck Range
Most fleets in this range get the best economics from a deliberate split:
- In-house: Routine PM (oil, filters, fluids, tires), minor repairs, pre-shift inspections, DOT walk-arounds, and first-level triage. This work is executed by one or two lube-level employees or by drivers trained on basic maintenance tasks.
- Outsourced: Diagnostic work, emissions system service, brake and drivetrain work beyond basic adjustments, body electrical faults, and any repair requiring specialty tooling or software access. Outsourced as mobile service for trucks at the yard or job site, or as shop-in service for trucks that can be transported without risk.
This structure keeps internal labor at a lower wage rate appropriate to the task complexity, eliminates the tooling and training investment for complex work, and uses mobile service selectively rather than for everything.
The hybrid also creates a natural escalation path. When a driver's pre-shift inspection flags a fault code, the lube tech attempts first-level diagnosis. If the fault is beyond their capability, the mobile service call goes out. That triage step catches the simple ones internally and reserves the expensive service calls for work that actually requires them.
Scheduling and Documentation
One underappreciated advantage of outsourced or mobile service is that good providers maintain work order history. That documentation trail — every invoice tied to a VIN, with dates, mileage, and parts used — is the foundation of a defensible maintenance record for DOT compliance, warranty claims, and resale valuation.
In-house shops that don't run a shop management system often generate paper work orders that are incomplete, unsearchable, or lost entirely. The truck's service history becomes tribal knowledge rather than documented record. When that truck is eventually sold or traded, the missing records cost you in resale negotiation.
If you run in-house maintenance, invest in a fleet maintenance management system that captures every repair event with date, mileage, technician, parts, and labor. The cost is modest and the value at disposition is real.
Talk to us
Scissortail Fleet Services runs mobile maintenance for North Texas fleets of all sizes — if you're trying to figure out where the line is for your operation, we're happy to work through the numbers with you. Reach us at (940) 600-5131 or through /contact.