I'm from England so I hear it quite a bit I don't use it myself. I may be wrong, but my impression is that men use it more than women.

I'd use it and am from the East Midlands (Nottingham, Derby, Leicester) and it can even be used to mean 'goodbye'. In this region it is often combined with 'duck' (cheers duck) or 'duckie'. The word 'duck' is used as a friendly term for the person you are talking to and does not mean you have mistaken them for a water dwelling bird!

It's used more often in Australia, according to what I've noticed. I use it a lot too whenever I respond to something I agree and whenever I end the conversation on a positive note. I use thank you only whenever I'm being sincere or in a formal setting.

I hear it being used in South Africa too.

Cheers and thank you are two different words. When somebody helps us then we say thank you but when we celebrate like birthday, party etc then we say cheers. Hi I am from India and we use cheers.