Renewal price math: when is it cheaper to migrate?

Built a spreadsheet. Migration cost vs renewal hike. Numbers looked clean until DNS entered.

Provider A renewal: $48/yr
Provider B equivalent: $28/yr
Migration time: 2 hrs @ $50/hr = $100
Break-even: never

but: Provider A hikes to $72
Provider B holds: $28
Migration time: 2 hrs
Break-even: year 2.1

Missing piece: TTL. Route via stale DNS adds 300s-86400s of downtime. Low TTL costs money at some providers. Forgot to bill myself for that.

https://dnschecker.org

Pro tip: Oracle free tier makes this math weirder because egress is metered and you will not notice until month three.

• Set TTL to 300s at least 48 hours before any migration. Heads up: some registrars charge for sub-3600s TTL.
• Run both stacks parallel for one full TTL cycle. Double cost, zero downtime.
• Check your cert renewal dates. Migrating three days before LetsEncrypt expiry is a self-inflicted wound.
• Your time is not free. Track it honestly. I bill myself at zero and still lose.

Real cost of my last migration: $7 saved, 4 hours spent, one crying session. Would not automate.