Ask most people what is inside their PC and you will hear something like "I think it has 16GB of RAM and a 750W something." That vagueness costs money and time. The moment you need to upgrade, claim a warranty or replace a failed part, "something" is not good enough. You need the exact model, and you almost never remember it under pressure.
The fix is humble and powerful: a bill of materials, or BOM. It is simply a written list of every component in your build, with the details that matter. It sits quietly alongside your other good habits, like a quarterly maintenance checklist and a pre-swap backup routine, and it makes every one of them easier.
What a bill of materials actually is
A BOM is a single document that lists every part in your machine alongside its exact model, and ideally its serial number, purchase date, price and the shop you bought it from. That is the whole idea. Most people never write this down, then regret it the first time they need it.
The value is precision. Instead of "a 750W something" you have "Corsair RM750x, serial ending 4471, bought 12 March 2025 from a shop in Computer Village for ₦185,000, three-year warranty." One of those sentences lets you act. The other leaves you guessing.
What each field buys you
Every column in a good BOM earns its place. Here is what each one does for you in practice:
- Exact model — this is the workhorse. It lets you check compatibility before an upgrade (which socket your motherboard uses, which RAM type and speed it takes), find the correct drivers, and order matching parts such as custom PSU cables or the right cooler bracket. Vague descriptions cannot do any of this.
- Serial number, purchase date and receipt — this is your warranty lifeline. Nigerian warranty cover very often hinges on proof of purchase plus the part's serial, so a BOM that captures both makes a claim straightforward instead of a scramble. It is worth understanding what to look for in a PC warranty before you need it.
- Price and shop — recording what you paid and where helps you track your spend, gauge realistic resale value later, and know exactly where to return for support if a part misbehaves.
Why it matters for maintenance and upgrades
This is where a BOM stops being paperwork and starts saving you. The most common jobs all depend on knowing what you already have:
- Adding RAM — to expand memory cleanly you need the exact existing kit, including its capacity, speed and timings, so the new sticks match. Mismatched RAM can refuse to run at full speed, or refuse to run at all. The BOM gives you that detail instantly.
- Planning a PSU swap — when a power supply is ageing you need to know its wattage and how old it is to plan the replacement sensibly. Those two facts shape the whole decision, which is why they feed directly into knowing when and what to look for in a PSU upgrade.
- Replacing a failure — when something dies, the BOM lets you identify the exact part to source, rather than opening the case and squinting at a label.
- Before any swap — checking the BOM first tells you precisely what you are dealing with, which is simply good pre-swap discipline alongside backing up your data.
How to build one
You can write a useful BOM in under an hour, and you only do the bulk of it once. Work through your machine part by part:
- List every component: CPU, motherboard, RAM (kit model plus capacity and speed), GPU, PSU (wattage plus model), each storage drive (model plus capacity), CPU cooler, case, fans and your operating system licence.
- For each one, record the model, serial number, purchase date, price, shop and warranty length. A row per part is enough.
- Snap a clear photo of the actual labels and serials while the machine is open or before you install. They are genuinely hard to read later, buried inside a built PC.
- Keep all your digital receipts together in one folder so the proof of purchase lives beside the record.
- Store the BOM somewhere you will not lose it — a cloud document you can open from your phone, plus a printed copy tucked in a drawer.
Keep it current, and scale it if you need to
A BOM is only as honest as its last update. The moment you change a part, update the document — a stale record is worse than none, because it confidently tells you the wrong thing. Make updating it the final step of every upgrade.
For a household with a single PC, this is a personal habit that pays for itself the first time you upgrade. For a business running several machines, the same idea scales into proper asset tracking, where it is worth moving up to PC inventory and asset tagging so every machine is accounted for. Either way, a BOM slots neatly into your wider maintenance routine.
Frequently Asked Questions
Do I really need serial numbers if I have the receipt? Yes, ideally both. The receipt proves you bought the part and when; the serial ties that proof to the specific unit in your machine. Nigerian warranty processes frequently ask for the serial, and reading it off a component already installed is awkward, so capturing it up front saves real hassle.
What if I bought my PC pre-built and do not know the exact parts? Open it up, photograph the labels, and note what you can read; many models are printed directly on the component. Check any invoice or build sheet from the shop. It is worth the effort, because the same details drive every future upgrade and future-proofing decision you will make.
How often should I update the BOM? Only when something physically changes — a new drive, more RAM, a fresh PSU. There is no schedule to keep; you simply treat updating the document as part of finishing any hardware change, so it never drifts out of date.
The One Thing to Remember
A bill of materials converts the vague "I think it's a 750W something" into precise, actionable information you can rely on for years. It costs an hour to create and a minute to update, and it pays you back every single time you upgrade, troubleshoot or claim a warranty.
Want help building a machine worth documenting? Start with our configurator to spec out the exact parts, and get in touch if you would like us to put together a clear build sheet you can keep from day one.