Can you leave Germany with a D-type visa and re-enter?

After you enter Germany with a D-type visa (national visa), it's generally recommended that you don't leave the Schengen Area until you've received your residence permit (Aufenthaltstitel). Once you have your residence permit, you can travel freely within the Schengen Area and re-enter Germany with that document. However, travel regulations, especially during special circumstances like pandemics where additional rules such as quarantine might apply, can change. Always check the current rules before you travel.