"Statusfeststellungsverfahren" is an (gov) insurance thing (the process is run by the "Rentenversicherung" (the pension fund)), it has (I think, not a lawyer) nothing to do with the Finanzamt (German IRS). That is an entirely different thing.
> The possibility to use private insurance depends on having some minimum amount of income.
This is incorrect. If you are self-employed you are off the state records. You can yourself choose to insure yourself using the gov insurances ("Freiwilligenversicherung"). But that is _usually_ an awfully bad deal (though ethically the right thing to do and I personally hope they eventually do the "Bürgerversicherung", which will level the terms for everyone).
The minimum income thing is only for dependent(regular)-employees. They are forced to be in the gov-insurance unless they exceed a certain income. If they do, they can choose (which often makes sense because private insurance has way better benefits and is way cheaper if you (consistently) have a high income (I don't know the current rate, 14% for the employee and 12% for the employer [and both if you are self-employed?])).
> Also, I currently use the option to use public insurance (voluntarily) so that I can easily switch back to it once I become employed again in the future.
They have to take you back unless you are 50+ I think (google the details). If you are dependently employed you _have to_ be in the gov insurance unless you exceed the minimum income. Buckle up, it's the law!
Because of that many privately insured people therefore often seek to get back into regular employment if they get closer to 50, to properly exploit the system.
> Apparently, there is some risk of not being accepted by the public insurers after one had quit.
This is age specific. Generally at least the "AOK" (kinda the fallback gov insurance company) has to always take you. In fact I think even private insurances _have to_ take you since quite a few years now - it's awfully expensive, but you are never supposed to be uninsured in Germany.
I might be wrong, but they only have to take one if you are below a certain age _and_ below the border income (Beitragsbemessungsgrenze). Always be careful w.r.t. these kinds of decisions because they could cost you an awful amount of money later.
If you are above the border income, the private version is less expensive (I might also be wrong, checkout https://www.finanztip.de/pkv/pkv-basistarif/). It only really affects people below that income (way too many!).
It is the reverse, staying in the gov insurance costs you an awful lot of money upfront. It's the ethical but financially stupid thing.
True, the private insurance is typicall less expensive now (when I researched, it was 50%-60% of what I pay), but you have no guarantee that it will stay that way. They could just increase the fees for everybody, in the future, or just increase it with your age, as the health risks go up.
What you say about voluntary public insurance is true: I currently pay the full amount (both parts, for employer and employee).
It's based on an estimate for my yearly gross income based on last year's tax report. The insurance (TK) assured me that I would get refunded what I overpaid each year. This is relevant, since I work much reduced hours due to family obligations. But I still have to pay forward the higher estimates for tax and insurance now...
> The possibility to use private insurance depends on having some minimum amount of income.
This is incorrect. If you are self-employed you are off the state records. You can yourself choose to insure yourself using the gov insurances ("Freiwilligenversicherung"). But that is _usually_ an awfully bad deal (though ethically the right thing to do and I personally hope they eventually do the "Bürgerversicherung", which will level the terms for everyone).
The minimum income thing is only for dependent(regular)-employees. They are forced to be in the gov-insurance unless they exceed a certain income. If they do, they can choose (which often makes sense because private insurance has way better benefits and is way cheaper if you (consistently) have a high income (I don't know the current rate, 14% for the employee and 12% for the employer [and both if you are self-employed?])).
> Also, I currently use the option to use public insurance (voluntarily) so that I can easily switch back to it once I become employed again in the future.
They have to take you back unless you are 50+ I think (google the details). If you are dependently employed you _have to_ be in the gov insurance unless you exceed the minimum income. Buckle up, it's the law! Because of that many privately insured people therefore often seek to get back into regular employment if they get closer to 50, to properly exploit the system.
> Apparently, there is some risk of not being accepted by the public insurers after one had quit.
This is age specific. Generally at least the "AOK" (kinda the fallback gov insurance company) has to always take you. In fact I think even private insurances _have to_ take you since quite a few years now - it's awfully expensive, but you are never supposed to be uninsured in Germany.