Was referred to this page <https://wiki.gentoo.org/wiki/Systemd> about enabling systemd as the init system in Gentoo. The section on “Timer services” I found particularly useful, as applicable to other distros running systemd: instead of a conventional crontab, you create .timer entries, and corresponding .service descriptions for them to invoke, in your ~/.local/share/systemd/user area. One advantage of this I can see is one less set of user files kept in /var. In fact, do this in conjunction with maildir format for user mail, and you no longer need to have any user files in /var. (That I can think of, anyway...)