The verdict in three sentences
Beyond 200 to 300 monthly contracts, recurring billing in spreadsheets costs more than a dedicated tool: missed invoices, late reminders and poorly tracked credit notes erode 3 to 5% of revenue. The choice is between a billing SaaS at 50-300 USD a month, which must be connected to your sales tax and accounting stack, and a custom app at 40,000-120,000 USD (market estimate in New York) delivered in 10 to 14 weeks. If your contracts are standard, start with SaaS; if your pricing rules are complex or billing is tightly tied to service tickets, custom pays back in under 2 years.
SaaS or custom: 2026 comparison for a New York SME
| Criterion | Billing SaaS (Chargebee, Stripe Billing, Zoho Billing) | Accounting add-on (QuickBooks recurring) | Custom app |
|---|---|---|---|
| Entry cost (market estimate) | 0 to 3,000 USD setup | 0 to 1,000 USD | 40,000-120,000 USD |
| Recurring cost | 50 to 300 USD a month, sometimes + 0.5 to 0.8% of billed revenue | 30 to 200 USD a month | Maintenance 500 to 2,000 USD a month |
| Sales tax (New York State and City) | Via Avalara or TaxJar connector, 50 to 300 USD a month | Basic | Integrated from design |
| Complex pricing rules (tiers, indexation, proration) | Good, within the built-in model | Limited | Unlimited |
| Link with tickets and field work | Via API, medium effort | Rare | Native |
| Setup time | 2 to 6 weeks | 1 to 3 weeks | 10 to 14 weeks |
| Data and code ownership | Data exportable, code not | Variable | Full |
New York taxes many IT services and software differently depending on the deliverable, and New York City adds its own rate on taxable sales. Before signing with a SaaS, check who configures and maintains the tax integration: that is often where the budget slips.
What the tool must do, and what it earns
| Function | In spreadsheets | With the tool | Estimated gain for 450 clients |
|---|---|---|---|
| Monthly invoice generation | 5 to 6 days of work | Automatic on the 1st | 4 to 5 person-days a month |
| Missed invoices | 3 to 5% of contracts | Near zero, completeness check | 3 to 4% of recurring revenue |
| Overdue reminders | Manual, irregular | Sequence at D+7, D+15, D+30 by email and SMS | Payment delay cut by 10 to 20 days |
| Annual price indexation | Forgotten one year in two | Applied automatically on renewal date | 2 to 5% increase actually billed |
| Proration on starts and cancellations | Hand calculations, errors | Automatic | Fewer client disputes |
| MRR and churn dashboard | None | Real time | Churn under control |
Mini case study
Jordan, founder of a 25-person managed IT services firm in New York, bills 450 clients at an average of 900 USD a month, or 405,000 USD monthly. With 4% of invoices missed, 16,200 USD goes unbilled each month; he estimates half is caught too late, so he loses about 97,000 USD a year. Add 5 days a month of avoidable billing work, around 18,000 USD a year. Estimated total gain: 115,000 USD a year. A custom app at 90,000 USD, linked to his ticketing tool, pays back in about 9 to 10 months; a SaaS at 300 USD a month with a 15,000 USD integration would pay back faster, but without the native link to service tickets that drives his time-and-materials billing. This scenario is illustrative.
FAQ
At what number of clients should we leave spreadsheets?
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In practice, from 150 to 200 monthly contracts or as soon as more than one person edits the file. Beyond that, the miss rate often exceeds 2%.
Does a billing SaaS handle New York sales tax?
Most connect to Avalara or TaxJar, which cost 50 to 300 USD a month. Taxability of IT services still needs to be reviewed with your accountant.
How long does a custom recurring billing app take?
As an order of magnitude, 10 to 14 weeks for subscriptions, invoices, reminders and a dashboard. Migrating existing contracts adds 1 to 2 weeks.
Can subscriptions be collected automatically?
Yes, via ACH debit or card payments through Stripe or similar processors. Fees typically range from 0.8% for ACH (capped) to about 2.9% plus 0.30 USD for cards.
Which metric should we track first?
MRR (monthly recurring revenue) and monthly churn. For a managed services firm, churn above 2% a month should trigger an analysis.
Let's scope your project. Send us your contract count, pricing rules and tax constraints: we compare SaaS and custom, then estimate the chosen solution with scope, indicative budget and timeline through our quote form. 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.
