I do a fair amount of international travel and typically have a local simcard to use in my iPhone wherever I am. When I upgraded from the 3GS to the 4, I had to get a whole load of new simcards and it seems like I'll be doing the same this time around. But I'm also a bit concerned that an iPhone I buy in one country may not be the same as an iPhone I buy in a different country and that when I try to use it, it may not work optimally with the local 4G network. I confess that I am completely ignorant of all the jargon here - GSM, CDMA, LTE, etc. So my question is whether I should (a) not worry about this at all, (b) buy my iPhone5 in Australia (where I live and spend most time), (c) buy it in the UK (my next most frequent destination), (d) stick to iPhone 4 or 4S. The countries I spend time in regularly (at least regularly enough to bother with a local simcard) are, in descending order of time spent ... Australia UK USA Spain Italy Thanks in advance for any advice/help!