Build vs Buy Software: A Decision Framework That Actually Works

Why Build vs Buy Is So Hard

The build vs buy decision feels high-stakes because it is. Choose wrong and you either waste $100K+ on custom software you didn't need, or spend years fighting with off-the-shelf software that doesn't fit.

The problem is most businesses make this decision based on gut feeling or cost alone. This framework replaces gut feeling with a structured scoring model.

The 7-Factor Scoring Model

Score each factor from 1 (strongly favors buy) to 5 (strongly favors build):

1. Process Uniqueness (Weight: 3x)

How different are your processes from industry standard?

• 1–2: Our processes are standard — any tool can handle them
• 3: Some unique aspects but mostly standard
• 4–5: Our processes are a competitive advantage — no tool replicates them

2. Integration Depth (Weight: 2x)

How deeply does this software need to connect with your other systems?

• 1–2: Standalone tool, minimal integration needed
• 3: Needs to connect to 1–2 other systems
• 4–5: Must be deeply integrated with 3+ systems, real-time data flow

3. Total Cost of Ownership (Weight: 2x)

Calculate 5-year TCO for both options. Score based on which is cheaper:

• 1–2: Buy is significantly cheaper over 5 years
• 3: Roughly equal cost
• 4–5: Build is significantly cheaper over 5 years (including workarounds, licenses)

4. Vendor Dependency Risk (Weight: 2x)

What happens if the vendor changes pricing, features, or goes away?

• 1–2: Low risk — many alternatives, easy to switch
• 3: Moderate risk — some alternatives, moderate switching cost
• 4–5: High risk — few alternatives, data locked in, switching is painful

5. Time to Value (Weight: 1x)

How quickly do you need this working?

• 1–2: Need it this week/month — buy is the only option
• 3: Need it in 2–3 months — either option works
• 4–5: Can wait 4–6 months — build is viable

6. Competitive Advantage (Weight: 2x)

Does having unique software give you an edge competitors can't copy?

• 1–2: No — this is a commodity function
• 3: Minor advantage
• 4–5: Significant advantage — our software IS part of our value proposition

7. Internal Capability (Weight: 1x)

Do you have the team/expertise to manage a custom solution?

• 1–2: No technical capacity — must buy or hire
• 3: Can manage with a development partner
• 4–5: Strong internal technical team

The Scoring Calculation

Weighted Score = (Factor × Weight) summed across all 7 factors

Maximum score: 13 × 5 = 65
Minimum score: 13 × 1 = 13

Interpretation:
  13–29  →  Strong BUY signal
  30–42  →  Lean BUY — but investigate custom for specific gaps
  43–52  →  Lean BUILD — but consider hybrid approach
  53–65  →  Strong BUILD signal

Real Example: Property Management System

Result: 52 → Lean BUILD. This agency should build a custom property management system, potentially with a hybrid approach for any commodity functions.

The Hybrid Option

Most build vs buy decisions aren't binary. Consider:

Full Buy:     Use off-the-shelf for everything
Hybrid:       Buy for commodity functions, build for differentiating functions
Full Build:   Build everything custom

Many successful businesses use off-the-shelf for email, accounting, and basic CRM, then build custom systems for their core operational processes.

What to Do Next

1. 01Score your situation using the 7-factor model above
2. 02If lean buy: Evaluate top 3 off-the-shelf options using a requirements matrix
3. 03If lean build: Define MVP scope and get 2–3 development proposals
4. 04If in the middle: Consider the hybrid approach — buy commodity, build custom

Key Takeaways

• Use the 7-factor weighted scoring model, not gut feeling
• Weights reflect what matters most: uniqueness, integration, TCO, vendor risk
• Score 13–29 = buy, 30–42 = lean buy, 43–52 = lean build, 53–65 = build
• The hybrid approach (buy commodity, build custom) works for most businesses
• The cost of indecision often exceeds the cost of either choice