We have scripts that have been running continuously for probably years at a time with none of these issues. The only time they stop is when servers are rebooted

We have scripts that have been running continuously for probably years at a time with none of these issues. The only time they stop is when servers are rebooted for updates. We actually had a big argument about building them like this for exactly the reasons you mentioned though - the preference for me and some others was to run them as once off's from cron, specifically to avoid the possibility of memory issues. Our tech lead wanted them to run as services (I think to improve responsiveness primarily). I didn't think it would work as well, but history has proven that it worked fine. I can't say it was better - it took a while to work out the kinks - but these things have been happily running for over a decade with basically zero issues relating to memory leaks, etc. They're not super complicated but not trivial either.