Would your Norton Security Suite still work without subscription? (Apart from no new definition.)
If so, you should still be fine without the latest definition for a while, just know what you are doing.
To me, I am too cheap to pay for the subscription for Virus Barrier (well, you know that Antony is poor). And I know that from time to time, there will be bundles/promotions of new Virus Barrier which comes with one year subscription. And the bundled price is always cheaper than the one year subscription cost.
As for the Windows (virtual machines) I have under Parallels Desktop for Mac, I don't have anti-virus/security suite installed on most of them, and only Microsoft's free one on one.
I think I shall let Windows users to comment on anti-virus applications.
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