The verdict in three sentences
The real problem for a consulting or HR firm is not invoicing, it is the utilization rate: every point lost on staffing costs tens of thousands of euros a year. A SaaS PSA (Professional Services Automation) is enough for most firms of 5 to 30 consultants, at 25 to 70 EUR/user/month. Custom software (45,000 to 140,000 EUR) is only justified when your staffing model, margin rules or payroll integration fall outside the standard mould.
What a firm-management tool must cover in 2026
A consulting/HR management tool ties together five building blocks: CRM and engagement pipeline, staffing and consultant planning, time tracking, per-engagement margin tracking, and billing. The switch to custom is decided block by block, not all at once.
| Functional block | Covered by SaaS PSA | Custom stake |
|---|---|---|
| CRM / engagement pipeline | Yes, standard | Rare |
| Multi-skill staffing | Partial | Frequent with complex matrix |
| Time entry | Yes | Rare |
| Per-engagement margin | Yes, basic | Frequent with variable rates |
| Fixed-price / T&M billing | Yes | Sometimes (mixed rules) |
| Payroll / HRIS integration | Limited connectors | Often decisive |
| Consolidated utilization reporting | Yes | If proprietary KPIs |
SaaS vs custom: the real 5-year cost
The per-user headline price hides the true trade-off. Here is a 2026 order of magnitude for a 20-consultant firm.
| Criterion | SaaS PSA | Custom |
|---|---|---|
| Cost per consultant / month | 25 to 70 EUR | 0 EUR (no license) |
| Year 1 cost (20 users) | 6,000 to 16,800 EUR | 45,000 to 140,000 EUR |
| 5-year TCO (20 users) | 30,000 to 84,000 EUR | 60,000 to 175,000 EUR |
| Payroll / HRIS integration | 3,000 to 12,000 EUR | Included in scope |
| Time to deploy | 4 to 10 weeks | 5 to 10 months |
| Fit to staffing model | 70 to 85 % | 100 % |
| Vendor lock-in | High (subscription) | Low (code delivered) |
Over 5 years the gap narrows sharply beyond 25 users, or when the SaaS requires 3 to 4 paid connectors to approach your real process.
Mini case study
Sophie runs a 22-consultant HR consulting firm in Nantes. Her 2025 average utilization was 68 %. With an average day rate of 750 EUR and 210 theoretical billable working days, each consultant produces 68 % × 210 × 750 = 107,100 EUR/year. By tightening staffing and time entry with a dedicated tool, she targets 73 % utilization, i.e. 114,975 EUR/consultant, +7,875 EUR each. Across 22 consultants: +173,250 EUR of billable output per year. A 90,000 EUR custom build pays back in under 7 months of margin gain.
FAQ
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Is a SaaS PSA enough for a 15-person HR firm?
In most cases yes: at that size, a 25-70 EUR/user/month subscription covers staffing, time and billing. Custom becomes relevant mainly when your payroll integration or margin rules are atypical.
How much does per-engagement margin tracking cost in a custom build?
The margin module (variable rates, internal costs, subcontracting) generally represents 12,000 to 30,000 EUR in a custom project, depending on rule granularity and the number of rebilling scenarios.
What utilization gain can I expect?
A realistic gain is 3 to 6 utilization points in the first year, simply by removing planning gaps and reliable time entry. Across 20 consultants, each point is worth roughly 30,000 to 40,000 EUR of output.
Is payroll integration essential?
Not mandatory but highly profitable: it removes double time/payroll entry and firms up the internal costs used for margin. It is often the point that tips the decision toward custom.
How long for a custom deployment?
Plan 5 to 10 months: 4 to 6 weeks of scoping, then 2-week sprints. A phased rollout (staffing first, billing later) cuts risk and surfaces value earlier.
Let's scope your project. Tell us your consultant headcount, staffing model and current HRIS, and we will price SaaS vs custom with a 5-year TCO. 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.
