When to Replace an Off-the-Shelf SaaS with Custom Software in 2026

The verdict in three sentences

You don't leave a SaaS because you like it less, but when per-seat cost and lock-in suffocate the business. The objective signals are quantifiable: bill >30,000 EUR/yr, >40 % of features unused, 10-20 %/yr hikes and workflows worked around in Excel. If three of these signals align, custom becomes a profitable investment within 24-36 months, not a technical whim.

The four switch signals, quantified

These indicators let you decide without emotion. Review them before any decision.

One signal isn't enough. But when the bill exceeds 30,000 EUR/yr and 40 % of functions lie dormant and teams patch with spreadsheets, the equation clearly tips toward custom.

The real cost of a migration

Replacing a SaaS isn't free: data migration and the double-run period weigh as much as the build. Here are the 2026 benchmarks.

The double-run (running the old SaaS and the new tool in parallel for 2-3 months) is the most often forgotten item: budget for it. In return, you permanently remove the per-seat rent and regain code ownership, ending vendor lock-in.

Mini case study

Nadia, CFO of a 180-employee distribution group, adds up four SaaS subscriptions at 48,000 EUR/year, including a per-seat management tool with a +15 % hike announced. Her audit shows 43 % of functions are never used and accounting re-keys 7 h/week in Excel. She launches a custom migration at 62,000 EUR (plus 11,000 EUR maintenance/yr and 8,000 EUR data migration). By year 3, cumulative TCO drops below the kept-SaaS path (hikes included), and she then saves ~35,000 EUR/year while eliminating the Excel re-keying.

FAQ

When should I replace a SaaS with custom? When several signals stack up: bill >30,000 EUR/yr, under 60 % of features used, 10-20 %/yr hikes and Excel-worked-around workflows. A single signal doesn't justify the switch.

What does a migration cost in 2026? Expect 30,000 to 80,000 EUR for the build, 5,000 to 20,000 EUR for data migration, plus 2-3 months of double-run and 3,000 to 10,000 EUR of training. Maintenance follows at 15-20 %/yr.

How long until the migration pays off? The ROI threshold is usually between 24 and 36 months, depending on user volume and the size of avoided SaaS hikes. Beyond that, each year widens the gap in your favor.

What is vendor lock-in and why avoid it? It's dependency on a platform whose code you don't own and whose data isn't easily exportable. Custom, with code transfer and free hosting, removes this continuity risk.

How do I secure the data migration? Through a prior audit, field mapping, a tested import and a 2-3 month double-run before final cutover. Budget 5,000 to 20,000 EUR for this critical step.

Let's scope your project. Send us your annual SaaS bill, your feature-usage rate and your headcount: we'll assess your switch threshold and price the migration (30,000 – 80,000 EUR). Detailed quote within 48 h. WhatsApp +221 77 596 93 33.