Foreign citizens that live here in Germany for quite a long time can consider obtaining German citizenship. Just as returning to the former home country is unmeant, naturalization can be advantageous as without German citizenship some passages might be obstructed.
With obtaining Germany citizenship you gain liberality in the European Union, such as travelling without a visa, protection from eviction orders, access to civil servant status and the right to participate in politics (active and passive vote). But the counterpart could be liability for compulsory military or community service.
Under certain conditions there is a claim for naturalization. Such a claim is only excluded if there is e.g. no adequate knowledge of the German language (§ 11 StAG). So it is very important make a motion at the right time.