ISR revalidation interval configuration for low‑traffic Next.js pages

Goal: Lower the compute cost of a Next.js page that receives infrequent traffic by choosing an appropriate revalidation interval for Incremental Static Regeneration (ISR) so that most requests are served from the CDN edge cache rather than triggering a serverless regeneration.

Uncertainty: While the framework permits arbitrarily large revalidate values (or false for fully static), there is no guidance on the maximum interval that still meets freshness requirements for the specific content, and it is unclear how varying the interval impacts the trade‑off between reduced function invocations and the risk of serving stale data during unexpected traffic spikes.

What is the maximum acceptable staleness for this page’s data given business or compliance constraints?
How should the revalidation interval be selected to minimize function invocations while keeping stale‑content risk within that threshold?