It should be totally unnecessary, but not only that, it may present you with the very problems that you were trying to avoid in the first place.
It's unnecessary because the user should always ensure that his/her firewalls are correctly configured and/or the firewall should be sorting out the rules. When and how that happens depends very much on how the firewall needs to be configured - whether it happens automatically, or it asks the user for a permit/block response whenever something new happens, or perhaps needs fully manual configuration.
It's a potentially bad idea because a firewall that has just been installed needs a lot of configuring - if it prompts you, you will spend the first couple of days answering a lot of pop-ups, and if it needs manual configuration, that's a lot of work for you. With automatic rules, you still need to check them as you would have done had the firewall been left in place, except that those rules are potentially more likely to be wrong or missing completely, because they have been (or not) created in response to an existing configuration rather than a new event.
It's a lot easier just to leave it installed and running, then deal with it as appropriate.