I'm sure that the OP can use care and write a solid, non-leaking daemon that would run for years. I did not mean to disparage OP's daemon, coding, or any monitoring software.

I did mean that there are millions of lines of very clever code holding up that daemon, and it is impractical to test that code for months of constant operation. So as a precaution, monthly server restarts will do two things:

1. Prevent any long-term leakage problems from rearing their ugly heads
2. Catch any configuration changes that might have been made in the preceding month that would prevent the server from returning to normal operation. A failed restart at the beginning of a maintenance window is much easier to deal with than a failed restart after a move or extended power outage.