change Apple store to a different country

You should only change the iTunes/Mac App Store that you use if you have legally become a resident of another country and you are changing your account to the store for that country.

Even then, you will lose all of the information in your Purchases list and you will no longer receve update/upgrade alerts on any of your previous app purchases.

Late 2012 Mac mini, OS X Yosemite 10.10.3; Apple Watch, 38 mm silver AL, Watch OS 1.0.1; iPad Air 2 & iPhone 6+, iOS 8.3