* Mitosis itself is a single division process. During mitosis, a single parent cell divides into two identical daughter cells. So, in that sense, every cell that undergoes mitosis divides once.

* However, some cells only undergo mitosis once in their lifetime. For example, nerve cells (neurons) and muscle cells generally don't divide after they've matured.

So, it depends on what you're asking! If you're asking how many times a cell divides during the process of mitosis, the answer is once. If you're asking which cells only divide once in their lifetime, then it's a wider range of cells, including neurons and muscle cells.