If your product costs too much to build, you'll feel it everywhere. Margins get too thin to sustain a business, retail pricing struggles to stay competitive, and scaling becomes difficult. In the worst cases, the product doesn't survive contact with the market.
The frustrating part is that by the time most teams realize their cost problem, it's already too late to fix cheaply. Cost isn't patched in at the end — it's baked into the design from the very first decisions: which microcontroller, which enclosure strategy, which components make it onto the BOM. Here are ten design mistakes that quietly drive up product cost, and why catching them early is one of the highest-leverage things a hardware team can do.
1. Over-engineering the design
This is the single most common way to waste money on a hardware product — especially for first-time creators eager to build something impressive from day one. Wireless charging sounds compelling on paper, but for most products a simple USB-C connector does the same job for a fraction of the cost. The same pattern shows up in processor selection: reaching for an overpowered microcontroller doesn't just add component cost, it adds power consumption, heat, board size, and firmware complexity. Simpler designs are cheaper to build, and usually more reliable too.
2. Overly expensive PCB design
The PCB is one of the most expensive parts of a product to fabricate and assemble, and cost can spiral without careful layout decisions. A board larger than necessary wastes material; a board shrunk too aggressively forces extra layers, tighter routing, and blind or buried vias — all of which raise cost significantly. Mixing through-hole and SMT unnecessarily, or specifying fine-pitch packages that need special handling, pushes assembly cost up fast. Our electrical engineering team treats board simplicity and manufacturability as first-class layout constraints, not afterthoughts.
3. Choosing over-specified components
This mistake is subtle but compounds quickly: a voltage regulator rated for an amp when the product only ever draws 200mA, a temperature sensor with far more precision than required, an outdoor-rated connector on a product that only ever sees indoor use. Each case looks harmless alone. Multiply it across twenty components on a BOM and unit cost has quietly crept up by several dollars. Start from actual performance requirements and choose the cheapest part that meets them with reasonable margin — not 10x margin "just to be safe."
4. Reaching for custom parts too early
Custom batteries, chips, and radios let a product be exactly as optimized as possible — but unless volumes are already high, custom parts are usually a mistake early in development. They bring engineering cost, expensive tooling, long lead times, and often a single-supplier lock-in. An off-the-shelf battery pack may not use every cubic millimeter as efficiently as a custom one, but it's cheaper, safer, and available immediately. Custom components can come later, once volume justifies the investment.
5. An overly complex — or unnecessary — display
Displays are among the most expensive parts of many products, not just in component cost but in what they force the rest of the system to become: a more powerful processor, a bigger battery, more complex firmware, sometimes an entire GUI framework. If a product already pairs with a smartphone, BLE plus a companion app can serve as the whole interface. No display means a lower BOM, simpler firmware, better battery life, and a meaningfully cheaper product.
6. Using brand-name parts without a real need
Brand-name components make sense for critical functions — microcontrollers, radios, power supplies, anything safety-related. But for passives, analog switches, level shifters, and logic gates, a big-name part from a premium supplier often isn't necessary. Reputable lower-cost suppliers offer generic parts that perform just as well, provided they're properly validated — samples tested, tolerances verified, a second source qualified.
7. Not designing for manufacturability (DFM)
Designing for performance and designing for production are two different disciplines. A design that looks excellent on paper but is difficult to assemble, solder, or inspect on a production line costs more to build — through slower assembly, higher defect rates, and increased labor. Good DFM practice makes a product cheaper and more reliable at the same time, which is why we build it into mechanical engineering and manufacturing support from day one.
8. Unnecessary mechanical complexity
A three- or four-piece enclosure often ships when a simple two-piece design would work just as well, and a complex mold requiring side actions or sliders drives up both tooling and per-unit cost. Fasteners are another quiet offender: twelve screws where four would suffice, or screws where a snap fit would have done the job. Every additional part adds assembly time, sourcing complexity, and another potential failure point.
9. Skipping manufacturing cost estimates early
This is one of the biggest strategic mistakes in hardware development. Many teams build out the entire prototype — firmware, enclosure, everything — before getting a real manufacturing quote, only to discover the product will cost $80 to build when it was meant to retail at $99. By then the design is locked in, and redesigning for cost means delay and revalidation. Ballpark quotes on PCBs, components, enclosures, assembly, and packaging should start as soon as a system-level block diagram exists — not after months of development. This is exactly the kind of assumption that should get tested before you commit to tooling, the same way we frame it in Validate Before You Tool.
10. Ignoring power efficiency
Power inefficiency sneaks up on teams. A product that isn't power-efficient compensates with bigger batteries, larger regulators, heat sinks, and sometimes thermal protection circuitry — all of which add cost. It isn't only a hardware problem: firmware that keeps peripherals awake unnecessarily wastes power just as surely as an inefficient circuit does. Optimizing power efficiency early creates room for smaller components, smaller batteries, and simpler enclosures — lower cost across the system, with better battery life as a natural byproduct.
Bringing it together
None of these mistakes are exotic. They're the ordinary, easy-to-justify decisions hardware teams make every day — add the nicer feature, spec the safer part, build the more capable board — each reasonable in isolation, each one quietly compounding into a product that costs far more to build than it needs to. The fix isn't a single clever trick. It's discipline: starting from real performance requirements, getting manufacturing cost visibility early through prototyping, and treating simplicity as a design goal in its own right.
Want a second set of eyes on your BOM before it locks in? Talk to CoBuild Labs— or see how we've applied this discipline across real builds in our Work portfolio.