The verdict in three sentences
Under 12 staff, a vertical SaaS at EUR 25-60/user/month is almost always the right call: live in weeks, zero maintenance on you. Above 15 staff, or with specific processes (recurring engagements, time-based billing, deep ledger integration), custom software at EUR 40,000-100,000 pays off over 5 years. The real question is not the sticker price but the 5-year TCO and the productivity gained per employee.
Vertical SaaS or custom development
Practice management software covers four blocks: engagements and deadlines tracking, time capture, billing (fixed fee and time-based), and reporting (profitability by engagement and by client). SaaS pools these functions for the whole market; custom moulds them onto your actual organisation.
| Criterion | Vertical SaaS | Custom |
|---|---|---|
| Entry cost | EUR 0 to 3,000 (setup) | EUR 40,000 to 100,000 |
| Recurring cost | EUR 25-60/user/month | Maintenance 15-20 %/yr of build |
| Time to launch | 2 to 6 weeks | 4 to 8 months |
| Customisation | Vendor options only | Total |
| Ledger integration | Standard connectors | Custom, deep |
| Code ownership | No (rental) | Yes (asset) |
| Roadmap | Vendor's | Yours |
The 5-year TCO calculation
Compare for a 12-staff firm. On SaaS, assume an average of EUR 42/user/month: 12 x 42 x 12 x 5 = EUR 302,400 over 5 years, before price rises. On custom, a EUR 70,000 build plus 18 %/yr maintenance (EUR 12,600) gives 70,000 + (12,600 x 5) = EUR 133,000 over 5 years.
| Line item | SaaS (12 users) | Custom |
|---|---|---|
| Initial build | EUR 0 | EUR 70,000 |
| Year 1 | EUR 60,480 | EUR 12,600 (maint.) |
| Years 2 to 5 | EUR 241,920 | EUR 50,400 (maint.) |
| 5-year total | EUR 302,400 | EUR 133,000 |
| Ownership | Rental | Owned asset |
Custom becomes attractive as soon as headcount or usage intensity push the SaaS bill up. Below that threshold, SaaS wins on flexibility.
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Mini case study
Claire, managing partner of a 14-person accounting firm in Dublin, currently pays for 3 separate SaaS tools (engagement management, time, billing) totalling EUR 41,000/yr, with time-wasting double entry. An integrated custom tool at EUR 78,000, EUR 14,000/yr maintenance, would cut recurring cost below EUR 14,000/yr. Gross saving: 41,000 - 14,000 = EUR 27,000/yr. The build pays back in 78,000 / 27,000 ~ 2.9 years, before counting the double-entry hours recovered.
FAQ
What is the real break-even point for custom? As a 2026 order of magnitude, it appears between 12 and 15 staff, or earlier if you stack several overlapping SaaS subscriptions (often EUR 30,000/yr or more).
How much is annual maintenance? Maintenance of 15 to 20 % of build cost per year is the norm: for a EUR 70,000 build, budget EUR 10,500 to 14,000/yr covering fixes, evolutions and supervised hosting.
Can we integrate our production ledger software? Yes, via API or connectors. That is precisely the custom advantage: avoiding double entry between production and billing, often 20 to 30 % of admin time.
How long to deliver a custom tool? Plan 4 to 8 months by scope, with a first usable version (engagements + time) often live by month 3 in an iterative approach.
Can we start small and grow? Yes. An MVP at EUR 35,000-45,000 covering engagements and time, then billing and reporting in phase 2, spreads the investment and lowers risk.
Let's scope your project. Give us your headcount, current SaaS subscriptions and your two biggest pain points: we will cost SaaS vs custom over 5 years. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
