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•Hegemi Team

When Spreadsheet Inventory Management Breaks Down

Excel is where most BOMs start. Here's the exact point where it stops working—and what to do about it.

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The Spreadsheet Trap

There's nothing wrong with starting in Excel. It's fast, everyone knows it, and for simple BOMs it works fine.

The problem is that Excel doesn't break all at once. It degrades gradually. By the time you realize you need something else, you've built a maze of interconnected spreadsheets that nobody fully understands.

This post identifies the specific failure modes—so you can recognize them before they cost you.

Failure Mode 1: Hierarchical BOMs

A GPS receiver contains two antenna boards. Each antenna board contains components. In Excel, this requires:

Option A: Nested worksheets

  • One sheet for GPS receiver BOM
  • One sheet for antenna board BOM
  • Manual cross-references
  • Update one, forget to update the other

Option B: Indentation in a single sheet

  • Works until you need the same subassembly in multiple parents
  • Copy-paste means drift
  • "Which version of the antenna board BOM is current?"

Option C: Relational structure with ID references

  • Now you're building a database in Excel
  • VLOOKUP chains that break when rows move
  • Only the original author understands it

Hegemi: Define the antenna board BOM once. Reference it from any parent. Changes propagate automatically. Revision history preserved.

Failure Mode 2: Instances vs. Definitions

Your BOM says "8 screws." You're building 5 units. Questions Excel can't answer easily:

  • Unit 3 has 6 screws attached. How many does it still need?
  • One unit failed QA and is being rebuilt. What's its current state?
  • Which units are complete enough to ship this week?

The spreadsheet "solution": Another sheet tracking unit status. Manual updates. Inevitable sync issues.

Hegemi: Each unit is an instance with slot-by-slot attachment tracking. Query completion status programmatically. No manual sync—attachment events update state automatically.

Failure Mode 3: Attachment History

Customer calls: "Unit SN-2847 is failing. Was anything changed during manufacturing?"

Excel answer: Check notes columns. Search email. Ask the build team. Hope someone remembers.

Hegemi answer: Pull up SN-2847. Every component attachment/detachment is timestamped with user attribution. Full history, 30 seconds.

This isn't just about customer support. It's about:

  • Regulatory compliance (FDA, AS9100, etc.)
  • Root cause analysis when issues emerge
  • Protecting your company when questions arise

Failure Mode 4: Multi-Source Parts

You can buy those screws from three vendors:

  • Vendor A: $0.05 each, minimum order 1000
  • Vendor B: $0.08 each, minimum order 100
  • Vendor C: $0.12 each, no minimum, same-day shipping

In Excel, this becomes:

  • Multiple rows per part? (Breaks BOM structure)
  • Separate vendor sheet with lookups? (Maintenance nightmare)
  • Notes column? (Unstructured, unsearchable)

Hegemi: Vendor items are first-class entities. Each item can have multiple vendor sources with price breaks, lead times, and notes. Inventory analysis considers all options when recommending purchases.

Failure Mode 5: Version Control

"Which version of the BOM did we use for the units we shipped in March?"

If your answer involves:

  • Searching file modification dates
  • Checking email attachments
  • Hoping the filename convention was followed
  • Asking someone who might remember

...then you don't have version control. You have archaeology.

Hegemi: BOM revisions are explicit. Each instance references its specific revision. Migrate instances to new revisions when ready. Old revisions remain accessible for units still using them.

The Scaling Threshold

Excel inventory management typically breaks between 50-200 distinct parts, or when any of these become true:

  • Multiple people edit inventory data
  • Subassemblies are reused across products
  • Serialized tracking is required
  • Customers expect traceability documentation
  • You've had a "which version" incident
  • Inventory counts don't match physical reality
  • Someone describes the spreadsheet system as "fragile"

Two or more checkmarks? You've hit the threshold.

Migration Isn't As Hard As You Think

The common objection: "We have years of data in these spreadsheets."

Reality check:

  1. Current inventory: A one-time import, usually a few hours of cleanup
  2. Historical data: Do you actually query it? Or just keep it "for reference"?
  3. BOM structures: Define once in Hegemi, never maintain parallel copies again

Hegemi offers bulk import specifically for this transition. Most teams are operational within a day.

What You're Actually Buying

Switching from spreadsheets to Hegemi isn't about features. It's about confidence:

  • Confidence that inventory counts are accurate
  • Confidence that build state is current
  • Confidence that history is complete
  • Confidence that the next person can understand the system

Spreadsheets optimize for initial speed. Hegemi optimizes for long-term sanity.

Ready to see the difference? Start with the tutorial—import your existing data and experience what structured inventory management feels like.