To this day, every Sunday I get e-mail via a cron job that runs domain-check against a set of about three dozen domains (mine, friends', and those of institutions I care about) to tell me which of them are within 90 days of expiration (and if any are past expiration).
FYI, here's an example report sent using said cron job, that leverages Ben Okopnik's 'domain-check' Perl script:
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Date: Sun, 24 Dec 2017 07:12:02 -0800 From root@linuxmafia.com Sun Dec 24 07: 2:02 2017 From: root <root@linuxmafia.com> To: rick@linuxmafia.com Subject: domain-check: Domain expiration warning (90 day cutoff)
According to 'whois', these domains will expire soon:
Unfortunately you can't poll whois for a .au domain more than 20 times a day from the same IP. Australian domain whois also doesn't show expiry info.