As a term I never I tend to use it interchangeably with people I know - "Howat mate" or "Howat Steve" both to the same person that I know - or, like most, when I don't know who the hell they are - "excuse me mate, can you just squeeze past you there, cheers" - none of which I would associate as a term showing respect TBH.
I also use matey, buddy, fella, guys, folks, ladies, duck, miss, kid, kidda etc all very interchangeably for people I don't know as well (as per the example above they can all be used).