Do I need to repurchase apps if I moved countries?
So... unfortunately the answer is...

Yes, but there are ways around it...

All the apps you bought in country A are permanently assigned to your AppleID. Once you move to country B and you updated your details (billing address) you:


still can use them
you cannot re-download them
you cannot update them
you cannot convert your music to iTunes Plus (but still can listen, obviously)


There are two solutions to this:


Switch Store's country and update your billing details each time you want to get your apps up to date (or re-download them). But this is a rather painful process, so a better solution is to...
Create a new AppleID with the billing details for the country B. Switching between AppleIDs is much easier and quicker than switching Store's country and updating your billing address.


Let me quote why it has to be this way:


  [...] this how iTunes has been designed.


So. It's gonna be problematic, but nothing can be done really. :(