Fatti gli affari tuoi (mind your own business) Fatevi gli affari vostri (my your (second plural) own business)

You know it really depends on the context: 1) Fatti gli affari tuoi! (Mind to your own business! = Don't bother me/ go away!) 2) Pensa agli affari tuoi (You'd better care much more to your business) For details, comment below. Bye

The most common way to express that sentence in italian is: "Dovrebbero farsi i fatti loro" oppure "Dovrebbero farsi gli affari loro".

(Lui / lei) dovrebbe occuparsi dei fatti suoi or dei suoi affari. (loro) Dovrebbero occuparsi dei fatti loro or loro affari.

I mind my own business. Mind your own business. (singular) He/She should mind his/her own business. They should mind their own business. (plural) We should mind our own business.