Re-installing Office:mac 2011 - Risk?

Hi, I have just purchased a new iMac and still happily using Office:mac 2011 on my old computer... I see that Microsoft are no longer supporting that version.

I have just re-installed 2011 but I am aware that the security for this version is now reduced. Thoughts... is there a major risk with using this version? Just seems a waste of money when there is nothing wrong with what I have..

Thanks.