AntiVirus No Longer Updating

It's personal choice at the end of the day.

Whilst some may argue that the greater threats come from malware etc nowadays, "traditional" virus threats still exist, so I'd prefer to have some defence against that. Just like their real world counterparts, they rarely go away altogether, but can lay dormant somewhere, awaiting an opportunity.

After all, once one gets on your system, there's no telling the havoc that may ensue.

Signatures are updated on a regular basis out of due diligence on the part of the AV providers, sometimes that's a brand new type of threat, others are variants on an existing threat where someone has tweaked an older instance - so the updated sig files help target that granularity.

Historically there have been cases of "old" viruses re-appearing and causing issues, and part of that was due to folks assuming older nasties were no longer a threat. All it takes is somebody, somewhere to open an old, infected file on an outdated or unprotected system, let's say a worm type, and that can then propagate at quite a rate if it finds similarly unprotected systems.

So what I'm saying there is don't discount historical threats, and a signature that potentially caters for that, although not subject to update is better than nothing. As for performance, there may be other ways to improve that, but my first stop wouldn't be to disable protection, up to date or not.