Analyze your domain's DNS TTL settings under two key lenses: Everyday Page Load Latency vs. Server Migration Readiness.
DNS Time-to-Live (TTL) is a numerical setting (measured in seconds) attached to every DNS record. It dictates how long recursive DNS resolvers, ISPs, and web browsers are permitted to cache your server's IP address before requesting a fresh update.
When you set a low TTL (e.g. 300s / 5 minutes) on a domain that is not migrating, every returning visitor's browser or local ISP must continuously send fresh DNS queries to resolve your server IP. This adds an extra 20ms to 150ms round-trip latency to page load times. For everyday stability, TTLs should be set to 3,600s (1 hour) or 86,400s (24 hours).
If you are planning to switch web hosts or move to a new server IP, follow this two-step process:
1. 24 hours BEFORE migration: Reduce your A and CNAME TTL values to 300s (5 minutes).
2. 24 hours AFTER migration: Once the new IP is verified stable, raise your TTL back to 3,600s or 86,400s to regain maximum DNS caching speed.