9. Assumptions and Open Inputs
The brief named a thesis (a system of record for one unglamorous trade) and asked for the trade to be chosen by research. It didn't give a team, trade access, geography, hours per week available, budget or stage. Here's what was assumed, and how the verdict changes if each assumption is wrong.
9.1 Assumptions made
| Input | Assumption used | If actually different… |
|---|---|---|
| Trade | Portable fire-extinguisher inspection and service, chosen from four (02) | If you have deep access to backflow testing, pest control or party rental instead, that access can outweigh the scores. A founder inside a weaker trade beats an outsider in the best one. Re-run the ladder for that trade. |
| Trade access | Available through the founder, a co-founder or a paid advisor (condition 1) | None: multiply every recommended figure by ~0.4. Don't start until it exists. |
| Hours per week available | Two plans: ~15 hrs/week and full-time (~40+) | Under ~10 hrs/week, the plan can't keep up with calls and migrations, so treat $1k–3k as the realistic ceiling. |
| Selling market | US shops, priced in USD | Canada or the UK: different standards (not verified), smaller markets, similar prices. Only after the US holds. |
| Founder location | Anywhere, but able to take live calls in US business hours | If US hours aren't possible, trial-led sales must work from day one, which is harder. Multiply by ~0.7. |
| Stage | Idea. No code, no users, no revenue. | Any paying shops change the conversation from "idea" to "evidence". Send the numbers. |
| Budget | $3–8k personal budget for labels, an advisor retainer, insurance and tools. No raise. | More money doesn't change the product advice. It changes how long you can afford to be wrong. |
| Pricing | Solo $69, Shop $179, Crew $329. Blended ~$150. | At a blended $100, every customer count rises by 50%, and $20k needs ~200 shops. |
| Market size | 4,000–8,000 US businesses service portable extinguishers (analyst estimate, not verified) | At ~2,000, $10k+ needs module 2 (hood suppression) or module 3 (backflow) by month 12. At 10,000+, the extinguisher-only ceiling rises. |
| NFPA 10 intervals | Annual maintenance, 6-year internal maintenance and 12-year hydrostatic test for common stored-pressure units (general knowledge, not re-read) | The due-date engine is rule-driven and editable, so the product survives this. The sales pitch must use the verified numbers. |
| Competitor strength at the low end | FireInspected and similar tools are small, with no clear winner | If one has thousands of shops and strong reviews, the $5k+ odds fall by about a third. Check before building. |
9.2 Inputs that would change the verdict most (please supply)
- Your trade access: who you know inside fire protection, extinguisher service or backflow, and how well.
- Hours per week available, and for how many months you can sustain them.
- Whether you can take calls in US business hours.
- Your technical background: can you build an offline-first PWA and imports yourself?
- Budget and runway: months of personal runway, and the monthly spend you're comfortable with.
- Any existing shops or distributors you could pilot with.
- Why this idea: interest in trades, or in the system-of-record thesis? A founder who finds the trade dull won't do 50 owner calls.
9.3 Definitions used throughout
- MRR ladder: chance of reaching each MRR level by month 24, profitable at that level. All odds are judgment estimates, anchored to proxies, because no verified base rate exists for bootstrapped B2B micro-SaaS (01).
- Tier A: $1M ARR within 36 months, ≥70% gross margin, ≥50% month-12 logo retention.
- Tier B: $20k+ MRR within 24 months, profitable, ≥80% gross margin, ≥70% month-3 retention.
- Shop: one paying business account, whatever its number of techs.
- Churn benchmark: SMB B2B SaaS loses about 3–5% of customers a month (Recurly ~3.5%). The target for this system of record is ≤1.5%.
- Small shop: 1–10 technicians.