When it comes to buy vs build software decisions, my view typically defaults to buying. I only recommend developing a small set of truly differentiating workflows where the standard tools cannot keep up.
My Core Stance as a Fractional CFO
As a fractional CFO, I strongly prefer to buy the core or foundation systems: ERP, AP/AR automation, payroll, FP&A/EPM, and basic analytics. I only build where the business model is unique enough that off-the-shelf tools either distort the process or block scale.
Simply put: buy your base application and selectively build the workflows that create a genuine competitive advantage around it.
Pros of Buying
Speed to market. Most SaaS models can be deployed and live within weeks, sometimes days. Internal builds, by contrast, take development teams quarters or even years depending on scope. Time to market matters when you are trying to fix reporting or tighten cash management, since clarity is the driving force.
Lower operational burden. There are two cost factors here: housing a full IT support team, and the process involved in upgrades, testing, and departmental sign-off. SaaS vendors amortize the costs of maintenance, security, upgrades, and feature development across thousands of customers.
Battle-tested practices. Off-the-shelf finance tools embed industry-standard processes for revenue recognition, close, compliance, and approvals, which reduces both design risk and audit friction.
Access to new innovation. You automatically benefit from improvements like AI-assisted forecasting, anomaly detection, and workflow automation, without funding or managing an internal product roadmap.
Focus on the business. Every hour the team spends “product managing” internal software is an hour not spent on pricing strategy, cash conversion, or M&A. That is a real opportunity cost.
Cons of Buying
Limited fit and flexibility. You are constrained by the vendor’s data model, workflow, and roadmap, which can be painful in complex or highly specialized businesses.
Subscription costs. As you grow, so do license tiers, add-ons, and integration fees. This drives up total cost of ownership, and unwinding from a deeply embedded vendor can be messy.
Integration friction. Stitching multiple SaaS tools together around a non-standard process can produce brittle workarounds and shadow systems in spreadsheets.
When I run into those ceilings, typically around complex pricing, unusual revenue models, or proprietary operational data, I start to consider building targeted components on top of the bought core.
Pros of Building
Designed for your reality. You can custom-code the actual logic, approval flows, or performance standards exactly as they operate in the business today, instead of forcing the business to mimic the software’s workflow.
Strategic differentiation. If you have a proprietary methodology, such as a unique credit engine, fraud detection approach, or capacity and pricing optimizer, owning that logic in your own stack can matter.
Control and ownership. You control priorities, data model, and release cadence rather than pleading with a vendor to move something up their roadmap.
Cons of Building
It is always harder and more complex than it looks. Successful internal tools require consistent product management, engineering, QA, security, documentation, and ongoing support. Scope creep and delays are the norm, not the exception. Recognize that reality going in.
Hidden lifecycle cost. After “version 1,” you still owe bug fixes, upgrades, scaling, refactors, compliance updates, and user training. Without sustained investment, the tool quickly lags and becomes a liability. There is no real end to this cycle.
Keyperson risk. If a small internal team or a single engineer owns the critical knowledge, turnover can strand you with an unsupported system that nobody wants to touch.
How I Make the Decision, Tool by Tool
I run each decision through a simple set of filters that mirror broader build-versus-buy frameworks.
Is this function strategic or a commodity?
Commodity functions like payroll, basic GL, standard CRM, and ticketing get bought every time. The market has already optimized these. Strategic functions like pricing engines or proprietary scoring models are where I will consider building or heavily extending a bought platform.
How urgent is the problem, and what is the time-to-value requirement?
If I need impact this fiscal year or quarter, I lean strongly toward buying. If I am designing for a multi-year transformation with the resources to stage a build, the door opens for custom work.
What is our true engineering capacity and appetite for owning a product?
If we do not have a stable, funded internal team with a mandate to maintain this for years, we have no business building it.
Can a blended approach work?
My preferred execution strategy is to buy a solid, dependable core system, then use low-code tools and scripting to meet specific needs, whether that is dashboards, micro-workflows, or decision engines. In practice, that means creating a custom stack tailored to the business. This approach reduces risk in every respect.
