Oh, I’ll have to explain my subject line using an example. 
When I execute ‘/usr/bin/letsencrypt renew’ I typically get the following (example) message on STDOUT.
Processing /etc/letsencrypt/renewal/www.example.com.conf
The following certs are not due for renewal yet:
/etc/letsencrypt/live/www.example.com/fullchain.pem (skipped)
No renewals were attempted.
It would be very helpful if the message would somehow include the foreseen expiry date(s):
Processing /etc/letsencrypt/renewal/www.example.com.conf
The following certs are not due for renewal yet:
/etc/letsencrypt/live/www.example.com/fullchain.pem (Expires on Jun 15 07:19:00 2016 GMT, Renewal possible starting Jun XX 07:19:00 2016 GMT)
No renewals were attempted.
In my case, especially since I run the renewal command from cron and I store all output from the command in a local logfile that I can then cat, grep, less, etc. I’d be able to very easily increase my attention when I come close to the moment when a renewal will become possible. And even more so, when coming close to the expiry date. (If I understand it correctly, the renewal will be possible before the expiry.)