You are obliged to notify the National Registry if you move. Your registered address is important as regards your rights and obligations in society. For example, it determines the municipality in which you can vote.
If you need to use public services, it is important that you are registered as being resident in the municipality concerned.
The National Registry provides a basis for population statistics. These statistics are for example important for the planning of nurseries, schools, housing developments, public transport, nursing home places and other public services.