Answer
Tests should run often enough that recovery steps stay current with infrastructure, application, staffing, and network change. The exact cadence depends on business criticality and audit pressure, but the risk comes from letting the plan age while assuming last year's test still proves this year's readiness.
Buyers should ask whether the software makes rehearsals easier to schedule, document, and review with business stakeholders. If testing is too disruptive or too manual to repeat, the plan will usually drift out of date.