I can see 15% changing daily. There's all sorts of stuff being done with dkim and other anti-spam technologies that require a txt or cname or whatever change in DNS. Companies are always whitelisting vendors and mass mailers to send as them, validating domain ownership, adding new sub-domains, changing things for Exchange/365/Google/AI stuff, changing things due to a security audit, etc.

I imagine a renewal is a change event to, at least change the expiry, and renewals are constantly happening.

> I imagine a renewal is a change event to, at least change the expiry, and renewals are constantly happening.

A domain renewal is an update at the registry, but there's no update in DNS at any level. If a domain expires, it would be removed (or at least changed) in the TLD DNS, but the authoritative DNS for the domain wouldn't necessarily update... it would just become orphaned.