What's the right way to monitor systemd services status

I'm trying to figure what's the right way for me to be notified when some systemd service is having problems. Manually checking systemctl status isn't a sustainable option; at the very least I want to have a simple tray icon, like just green or red. Some sounds and/or visual notifications can be useful too. Surprisingly I don't seem to find any existing tools for that, so the best I can think of is to write my own, maybe some simple bash script which would poll systemctl once in a while, and update the icon status. Pretty poor but alas. Before I actually start spending time on that, want to make sure, am I by any chance missing some better options?