One of the advanced features that firewall rules can have is a time constraint. It allows the rule to be activator a given period of time, on a given set of days.
From a security perspective, this is a great feature. It’s like locking up the house at night, or when nobody is home. Setting timing constraints on firewall rules can effectively block unauthorized or even malicious network activity when nobody is watching.
At home, a firewall rule time constraint can be used to turn off Internet access by the kid’s devices at bedtime on school nights, for example.
If the firewall allows Internet access to services being hosted locally, e.g. a website, access can be limited to those times when the resource is needed, and blocked the rest of the time. This won’t stop hackers, but it will sure make it difficult if they only have a small timing window in which to try and hack.