Many of the Ph.D. students have a doctoral agreement and are paid like an employee. So one enjoys both the rights and the benefits of an employee. Here below is shown the LUH model of a Doctoral agreement between the student and the advisor.
In addition, one of the other important aspects is what one needs to do when one falls sick. It is possible to take a holiday for up to two days without a sickness certificate. But beyond that, one needs a sickness certificate from a doctor. Below are some details regarding the same.