nixpkgs

Common ways of managing Nix packages include:

• nixpkgs-unstable
• nixos-unstable
• a stable release branch

I tend to use nixos-unstable because it provides newer and more recently updated packages compared to a stable version, while having more thorough testing and using less disk space than nixpkgs-unstable.

For more information on this topic, I’d recommend the following links:

• Nix channels for a high-level description of stable/unstable and related ideas
• Differences between Nix channels for a clear idea of available channels and their practical differences