A firewall that was configured once at installation and never revisited tends to accumulate rules nobody remembers the reason for, alongside gaps for services added since. We configure firewalls properly at the start and keep the rule set current as your business changes.
Ongoing management includes
Reviewing and retiring unused rules, applying firmware updates on a schedule rather than reactively, setting up logging that is actually useful during an incident, and adjusting policy when new locations, staff or applications come online.