Some examples of such these changes are updating the IP address of a server, updating your MX record to host your email at a new location, or adding a new website.The TTL setting tells the Internet how long to wait before returning to check your DNS record for potential new information.
It will partly depend on how long the lease is on the IP address.
The more often the IP address changes, the lower the TTL you should use.
TTL stands for “Time to Live” and it refers to how long your DNS settings are supposed to be cached before they are automatically refreshed.
When a DNS change is made, it takes time for the rest of the Internet to notice.
It is low enough for changes to take effect quickly, but not so low that the DNS servers get overloaded. While technically there is no maximum DNS TTL setting, values over 7 days will silently be rounded down to 7 days.