The five-minute rule comes from an MIT study on lead response times: contacting a new lead within five minutes — not an hour, not the same day — produces dramatically higher contact and conversion rates than waiting even a little longer. Every extra minute of delay measurably drops your odds of ever reaching that person at all.
For contractors, this is usually where the math falls apart in practice. Leads come in while you're on a roof, mid-estimate, or after hours — and by the time you call back, the customer's already talked to two other contractors who answered first. Speed to first response is one of the few genuinely controllable factors in close rate, which is why it's worth building a real system around instead of relying on catching your phone between jobs.
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Full breakdown: Speed to Price: Why the First Quote Wins