Local content caching on my MacBook
macOS Content Caching works by caching, on your Mac, requests to Apple servers from all Apple devices on your network. It was moved from Apple's Server app to be included as an integral part of macOS starting with High Sierra. You can see caching statistics on Activity Monitor &gt; Cache.
It works best when the caching computer is always on, particularly because client devices take a while to detect the caching server and start using it, but the server can run on any Mac. This detection is automatic for your local network, although you can configure specific rules for it.
You can also force client devices to detect the cache server immediately by restarting them or, if they're Macs, by running AssetCacheLocatorUtil on Terminal. The devices may stop using your caching server (and download directly from Apple) if they see it as unhealthy (down, non-responsive, or too slow). Each device decides this on its own so some client devices may see your caching server as healthy whereas others might see it as unhealthy.
It does take up storage space, however macOS by default will not count the cached data towards your used storage on  &gt; About this Mac &gt; Storage and, as far as I remember, will automatically purge old cache data when you try to use it for other purposes (such as copying files or installing apps).
To sum it up, you will probably not have &quot;low space&quot; problems, however, if you don't leave your Mac turned on for long stretches of time, you will possibly have little benefit of having it enabled.