Custom Software vs. SaaS: A Different Question Than "Build vs. Buy"
This isn't about whether an off-the-shelf tool is good enough — it's about who owns the software once it exists.
It's easy to conflate this with the more common "custom vs. off-the-shelf" question, but it's actually a different decision: not about fit, but about who owns the software once it's built, and how its cost is structured over time.
SaaS: you rent access, someone else owns the software
A SaaS product — whether a generic tool or a vertical one built for your industry — is owned and maintained by its vendor. You pay a recurring subscription for access, and the vendor handles hosting, updates, and infrastructure. You get to start using it immediately, but you're also bound by its roadmap, its pricing changes, and its decision to support (or drop) a feature you rely on.
Custom software: you own it, and you own the upkeep too
Custom software is built specifically for your business and, depending on the engagement, you own the code outright. Nobody else's roadmap decisions affect it, and it can be shaped exactly around your workflow. The tradeoff is real: you (or whoever you hire) are responsible for hosting, maintenance, and future changes — there's no vendor absorbing that cost into a subscription fee.
The actual decision points
Cost structure matters as much as raw price: SaaS is ongoing operating expense that scales with usage or seats; custom software is a larger upfront investment with lower (but non-zero) ongoing cost. Which is "cheaper" depends entirely on your time horizon and how long you expect to use the system.
Ownership matters if the software is core to your competitive advantage — a business whose entire value proposition depends on a workflow no one else has probably shouldn't be renting that workflow from a SaaS vendor who could change the terms. For a supporting function that isn't your differentiator, renting is usually the more sensible choice.