What is the ruling on combining the days of make-up fasting with the days of supererogatory fasting with the intention of joining them, and is it obligatory to repeat them, knowing that the one who did so continued it for ten years?

It is not permissible to combine the intention of making up for missed Ramadan fasts and observing a supererogatory fast in a single intention, according to the majority of scholars, because each of them is an act of worship intended for its own sake. In the case of combining them, scholars differ as to whether this suffices for the make-up fast or the supererogatory fast, or if it suffices for neither of them. The more cautious approach is to make up the fasts she observed with the intention of both make-up and supererogatory fasts, if possible.