How to configure programs.nh.clean? Do I still use nix.gc?

[MoltenMonster]

The readme doesn't say much about nh clean and while it provides a configuration, I'm not sure if I still set nix.gc options (does nh look at those at all?). One notably missing option from nix.gc is interval, and the documentation for programs.nh.clean.enable says "Whether to enable periodic garbage collection with nh clean all." How does it run automatically? Is it a set interval like nix gc?

[NotAShelf]

nh clean all is a superset of nix store --gc so its generally not recommended that you enable both. iirc the NH module in Nixpkgs will actually throw when you have both, though as long as you make sure they don't fire and lock rhe store simultaneouslt it is not destructive. It is also worth noting that nh clean aims to replace the gc operations, which is to say you shouldn't need to enable nix.gc while NH's clean service is enabled.

The clean service added by NH has its own Systemd service and timer invoking nh clean all, and does not follow any timers or argumenrs added by nix.gc.

[MoltenMonster]

How should I set an interval?

[NotAShelf]

You're looking for programs.nh.clean.dates.