Quoting Trent W. Buck (trentbuck@gmail.com):
If you have systemd, and you don't need to be an NTP *server*, consider "systemctl enable systemd-timesyncd" instead. This is installed but off by default in Debian 8; AIUI it will be the default in Debian 9.
*cough* Yes, stretch does indeed have this enabled by default. On new systems, I'm inclining towards openntpd, http://www.openntpd.org/ . Of course, this is for the use-case of wanting to have a functional ongoing ntp daemon, not just a Microsoft-style SNTP client with no error checking, authentication, no tracking of jitter or delay, no ability to consult more than one NTP server, and no precaution against adjusting the time jumps backwards, which is what systemd-timesyncd is. One nice thing, if you have a real ntpd running (ISC's or OpenBSD Foundation's or Chrony), then systemd-timesyncd quits gracefully (on systems where I've tested this, at least). And I personally feel much better running a real NTP implementation even on laptops.