I live in Austria (OE). There we have to change our call sign if we move beyond one of the 9 Austrian federal state's border. For example I lived near Innsbruck (Tyrol) with the sign OE7TKT. I moved to Graz (Styria) for studying - new call sign OE6TKT, next I moved to the capital Vienna - new call sign OE1TKT. Now I live in Klosterneuburg (Lower Austria) and I became OE3TKT.
Are there similar situations in other countries?
I know, in the US, you'll receive a call sign once and keep it as long as you are registered; in Germany (DL) too.
Tom OE3TKT (former OE7TKT,OE6TKT,OE1TKT), KW4NZ