I’d recommend learning/using systemd timers instead (well, if you are on inux and your distro uses systems)
You can use OnFailure
in your .service
file if you want some thing to happen when that specific service fails, but I don’t know if there’s a blanket way to tell systemd to notify via email when any failure happens (I wouldn’t mind a desktop notification… will investigate)
For another useful resource, this site is really helpful for decoding what cronjobs are in plain language.