Custom Software vs SaaS: When to Build vs Subscribe

The true cost of SaaS goes beyond the monthly subscription. Factor in: per-seat pricing that grows linearly with your team (10 seats at $50/month = $6,000/year; 50 seats = $30,000/year), add-on costs for features you'll eventually need, the 'integration tax' of connecting SaaS tools to each other (often requiring additional tools like Zapier at $50–$200/month), data export limitations if you ever want to leave, and the ongoing cost of adapting your processes to fit the software's assumptions.

The true cost of custom software: one-time development ($15K–$150K depending on complexity), hosting and infrastructure ($50–$500/month), ongoing maintenance ($500–$2K/month for updates and support), and future feature development (variable, as needed). Unlike SaaS, the cost doesn't scale linearly with team size — whether you have 5 users or 500, the software cost is the same.

When SaaS wins: the problem is common and standardized (email marketing, basic CRM, project management), you have fewer than 20 users, the SaaS tool covers 80%+ of your needs without customization, you need to be running within days not weeks, and you're okay with limited control over the product roadmap. For these situations, SaaS is the pragmatic choice.

When custom wins: the software is a competitive differentiator for your business, you need deep integration with proprietary systems, per-seat pricing will exceed custom development costs within 3 years, the SaaS tool requires significant workarounds for your workflow, you have data sovereignty or compliance requirements that SaaS can't meet, or you want to own and control the software long-term.

The crossover calculation: take your current SaaS spend for the tool in question, multiply by 36 (3-year cost), and compare to a custom build quote. If custom is within 50% of the 3-year SaaS cost, it's usually worth building — because you get exactly what you need, you own it outright, and the cost stays flat as you grow. For fast-growing businesses, the crossover from SaaS to custom often happens sooner than expected.

A real example: a 25-person company paying $150/month per seat for a project management SaaS = $45K/year. Over 3 years = $135K. A custom project management tool built for their specific workflow costs $60K. The custom tool pays for itself within 18 months and delivers exactly the features they need — not the 200 features they pay for but never use.