I have been using daemontools for managing my services on FreeBSD servers that have run 24/7 for almost a quarter of century, with down times of an hour or so only at intervals of a few years of continuous running, whenever I made a hardware upgrade or a complete OS replacement (by passing to another major version of FreeBSD).

Now there are several daemontools derivatives that bring it more up-to-date, but even the ancient original version did most of one would need for reliable service management.