The Domain Name Server has a TTL (Time to live) associated with it in seconds. For example: A TTL of 3600 means in one hour, it will request updated information on the domain, otherwise, it will continue to use it’s cached result.
How do I find out when to expect it to refresh? On windows use: nslookup -debug <domain> <name server>
nslookup -debug wordpress.org 126.96.36.199
opcode = QUERY, id = 1, rcode = NOERROR
header flags: response, want recursion, recursion avail.
questions = 1, answers = 1, authority records = 0, additional = 0
188.8.131.52.in-addr.arpa, type = PTR, class = IN
name = google-public-dns-a.google.com
ttl = 21575 (5 hours 59 mins 35 secs)