Direct answer
Don't frame this as engineering priorities versus business priorities; translate the technical debt into the same currency the business leader already tracks: revenue at risk, customer-visible failures, and opportunity cost of the growth work. Then propose a specific, time-boxed allocation (not an open-ended commitment) with milestones the leader can check without knowing the underlying code. The business case works only if the number is derived transparently enough that the leader could recompute it themselves.
Structured elaboration
- Quantify the cost of doing nothing. Count incidents per month, estimate the user-facing impact of each (failed transactions, dropped sessions, support load), and convert that into lost revenue and cost using numbers the finance side already trusts (active users, average order value, support cost per ticket).
- Size the ask precisely. State the allocation in engineer-time and dollar cost, not vague "some time." A leader can evaluate "4.8 engineer-months at $57,600" far more easily than "a chunk of the quarter."
- Show the expected return, with the assumption stated explicitly (for example, "if this work cuts incident frequency by 60%, here is the payback period"), so the leader is evaluating the logic of the estimate, not taking it on faith.
- Time-box it with milestones, so the ask reads as a bounded pilot with a checkpoint, not a permanent tax on the roadmap. This is also the honest framing: technical debt work has real diminishing returns, and an open-ended commitment invites (correctly) more scrutiny than a bounded one.
- Report against the same metrics you proposed, on a cadence the leader already reviews other initiatives on, so the debt-reduction work isn't the one line item nobody can evaluate.
This same tension shows up outside pure reliability work too: a mobility company deciding whether to invest an engineering quarter in routing-algorithm quality improvements versus building out a new traffic-data pipeline for market expansion is the identical trade-off (engineering-investment quality versus market-facing growth pressure), and the same translate-to-revenue-and-time-box approach applies regardless of which specific system is at stake.
Worked example
Assume 1,000,000 monthly active users (MAU, i.e. users active in a 30-day window), roughly 33,333 daily active sessions, an average order value of $40, and 4 outages per month, each of which drops conversion by one percentage point among that day's sessions:
Lost orders per incident=33,333×0.01≈333
Lost revenue per incident=333×$40≈$13,333
Monthly loss=4×$13,333≈$53,333
Annualized loss≈$53,333×12≈$640,000
For the ask: 8 engineers, a 12-week quarter, 20% allocation:
Engineer-weeks=8×12×0.20=19.2 (about 4.8 engineer-months)
Cost=4.8×$12,000/engineer-month=$57,600
If this work is expected to cut incident frequency by 60% (the assumption to test, stated explicitly, not a guaranteed outcome):
New annual loss=$640,000×(1−0.60)=$256,000
Annual savings=$640,000−$256,000=$384,000
Payback period=$384,000$57,600×12 months≈1.8 months
That payback period is the number to lead with in the ask, because it's the one figure a revenue-focused leader can sanity-check against their own model of the business.
Trade-offs & pitfalls
- Pitfall: presenting the 60% incident reduction as fact. It's a target the milestone plan should validate mid-quarter, not a promise; a leader who later finds the number was asserted, not measured, stops trusting the next ask.
- Pitfall: an open-ended allocation. "20% of engineering time on debt, ongoing" reads as a permanent tax; "20% for this quarter, with a week-6 checkpoint on incident trend" reads as a bounded, revocable pilot.
- Trade-off: speed of the growth work still slows down. Even a well-justified 20% allocation is 20% less growth-feature throughput that quarter; the honest version of the business case says this explicitly rather than implying the trade-off disappears once revenue math is attached.
- Senior signal: the difference between a competent and a senior answer here is usually the checkpoint and rollback path, not the size of the number. Anyone can compute a return on investment (ROI); fewer candidates propose a way to catch it if the 60% assumption turns out to be wrong at week 6.