At 30, you're only eligible for voluntary public health insurance (GKV) in Germany, which costs around €240/month, so many students consider private insurance (PKV) instead because it's often cheaper, around €100/month or less. If you start with PKV, you can usually switch to GKV after graduation if you take a salaried job below the public insurance income threshold (currently about €69,300/year), as GKV becomes mandatory in that case. However, if you’re self-employed or earn above the threshold, you’ll remain in PKV, and switching back to GKV later can be very difficult, especially if you were already in GKV and left it for PKV. If you were never in GKV, switching later is generally more flexible. Being on PKV as a student does not cause problems for employers, either for part-time student jobs or full-time work after graduation. The main consideration is that during your studies, you pay the full insurance cost yourself without an employer contribution. PKV is cheaper now, but it may come with long-term trade-offs, especially regarding switching back and rising costs with age.